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  <title>P1135R3: The C++20 Synchronization Library</title>
<style data-fill-with="stylesheet">/******************************************************************************
 *                   Style sheet for the W3C specifications                   *
 *
 * Special classes handled by this style sheet include:
 *
 * Indices
 *   - .toc for the Table of Contents (<ol class="toc">)
 *     + <span class="secno"> for the section numbers
 *   - #toc for the Table of Contents (<nav id="toc">)
 *   - ul.index for Indices (<a href="#ref">term</a><span>, in §N.M</span>)
 *   - table.index for Index Tables (e.g. for properties or elements)
 *
 * Structural Markup
 *   - table.data for general data tables
 *     -> use 'scope' attribute, <colgroup>, <thead>, and <tbody> for best results !
 *     -> use <table class='complex data'> for extra-complex tables
 *     -> use <td class='long'> for paragraph-length cell content
 *     -> use <td class='pre'> when manual line breaks/indentation would help readability
 *   - dl.switch for switch statements
 *   - ol.algorithm for algorithms (helps to visualize nesting)
 *   - .figure and .caption (HTML4) and figure and figcaption (HTML5)
 *     -> .sidefigure for right-floated figures
 *   - ins/del
 *
 * Code
 *   - pre and code
 *
 * Special Sections
 *   - .note       for informative notes             (div, p, span, aside, details)
 *   - .example    for informative examples          (div, p, pre, span)
 *   - .issue      for issues                        (div, p, span)
 *   - .assertion  for assertions                    (div, p, span)
 *   - .advisement for loud normative statements     (div, p, strong)
 *   - .annoying-warning for spec obsoletion notices (div, aside, details)
 *
 * Definition Boxes
 *   - pre.def   for WebIDL definitions
 *   - table.def for tables that define other entities (e.g. CSS properties)
 *   - dl.def    for definition lists that define other entitles (e.g. HTML elements)
 *
 * Numbering
 *   - .secno for section numbers in .toc and headings (<span class='secno'>3.2</span>)
 *   - .marker for source-inserted example/figure/issue numbers (<span class='marker'>Issue 4</span>)
 *   - ::before styled for CSS-generated issue/example/figure numbers:
 *     -> Documents wishing to use this only need to add
 *        figcaption::before,
 *        .caption::before { content: "Figure "  counter(figure) " ";  }
 *        .example::before { content: "Example " counter(example) " "; }
 *        .issue::before   { content: "Issue "   counter(issue) " ";   }
 *
 * Header Stuff (ignore, just don't conflict with these classes)
 *   - .head for the header
 *   - .copyright for the copyright
 *
 * Miscellaneous
 *   - .overlarge for things that should be as wide as possible, even if
 *     that overflows the body text area. This can be used on an item or
 *     on its container, depending on the effect desired.
 *     Note that this styling basically doesn't help at all when printing,
 *     since A4 paper isn't much wider than the max-width here.
 *     It's better to design things to fit into a narrower measure if possible.
 *   - js-added ToC jump links (see fixup.js)
 *
 ******************************************************************************/

/******************************************************************************/
/*                                   Body                                     */
/******************************************************************************/

	body {
		counter-reset: example figure issue;

		/* Layout */
		max-width: 50em;               /* limit line length to 50em for readability   */
		margin: 0 auto;                /* center text within page                     */
		padding: 1.6em 1.5em 2em 50px; /* assume 16px font size for downlevel clients */
		padding: 1.6em 1.5em 2em calc(26px + 1.5em); /* leave space for status flag     */

		/* Typography */
		line-height: 1.5;
		font-family: sans-serif;
		widows: 2;
		orphans: 2;
		word-wrap: break-word;
		overflow-wrap: break-word;
		hyphens: auto;

		/* Colors */
		color: black;
		background: white top left fixed no-repeat;
		background-size: 25px auto;
	}


/******************************************************************************/
/*                         Front Matter & Navigation                          */
/******************************************************************************/

/** Header ********************************************************************/

	div.head { margin-bottom: 1em }
	div.head hr { border-style: solid; }

	div.head h1 {
		font-weight: bold;
		margin: 0 0 .1em;
		font-size: 220%;
	}

	div.head h2 { margin-bottom: 1.5em;}

/** W3C Logo ******************************************************************/

	.head .logo {
		float: right;
		margin: 0.4rem 0 0.2rem .4rem;
	}

	.head img[src*="logos/W3C"] {
		display: block;
		border: solid #1a5e9a;
		border-width: .65rem .7rem .6rem;
		border-radius: .4rem;
		background: #1a5e9a;
		color: white;
		font-weight: bold;
	}

	.head a:hover > img[src*="logos/W3C"],
	.head a:focus > img[src*="logos/W3C"] {
		opacity: .8;
	}

	.head a:active > img[src*="logos/W3C"] {
		background: #c00;
		border-color: #c00;
	}

	/* see also additional rules in Link Styling section */

/** Copyright *****************************************************************/

	p.copyright,
	p.copyright small { font-size: small }

/** Back to Top / ToC Toggle **************************************************/

	@media print {
		#toc-nav {
			display: none;
		}
	}
	@media not print {
		#toc-nav {
			position: fixed;
			z-index: 2;
			bottom: 0; left: 0;
			margin: 0;
			min-width: 1.33em;
			border-top-right-radius: 2rem;
			box-shadow: 0 0 2px;
			font-size: 1.5em;
			color: black;
		}
		#toc-nav > a {
			display: block;
			white-space: nowrap;

			height: 1.33em;
			padding: .1em 0.3em;
			margin: 0;

			background: white;
			box-shadow: 0 0 2px;
			border: none;
			border-top-right-radius: 1.33em;
			background: white;
		}
		#toc-nav > #toc-jump {
			padding-bottom: 2em;
			margin-bottom: -1.9em;
		}

		#toc-nav > a:hover,
		#toc-nav > a:focus {
			background: #f8f8f8;
		}
		#toc-nav > a:not(:hover):not(:focus) {
			color: #707070;
		}

		/* statusbar gets in the way on keyboard focus; remove once browsers fix */
		#toc-nav > a[href="#toc"]:not(:hover):focus:last-child {
			padding-bottom: 1.5rem;
		}

		#toc-nav:not(:hover) > a:not(:focus) > span + span {
			/* Ideally this uses :focus-within on #toc-nav */
			display: none;
		}
		#toc-nav > a > span + span {
			padding-right: 0.2em;
		}

		#toc-toggle-inline {
			vertical-align: 0.05em;
			font-size: 80%;
			color: gray;
			color: hsla(203,20%,40%,.7);
			border-style: none;
			background: transparent;
			position: relative;
		}
		#toc-toggle-inline:hover:not(:active),
		#toc-toggle-inline:focus:not(:active) {
			text-shadow: 1px 1px silver;
			top: -1px;
			left: -1px;
		}

		#toc-nav :active {
			color: #C00;
		}
	}

/** ToC Sidebar ***************************************************************/

	/* Floating sidebar */
	@media screen {
		body.toc-sidebar #toc {
			position: fixed;
			top: 0; bottom: 0;
			left: 0;
			width: 23.5em;
			max-width: 80%;
			max-width: calc(100% - 2em - 26px);
			overflow: auto;
			padding: 0 1em;
			padding-left: 42px;
			padding-left: calc(1em + 26px);
			background: inherit;
			background-color: #f7f8f9;
			z-index: 1;
			box-shadow: -.1em 0 .25em rgba(0,0,0,.1) inset;
		}
		body.toc-sidebar #toc h2 {
			margin-top: .8rem;
			font-variant: small-caps;
			font-variant: all-small-caps;
			text-transform: lowercase;
			font-weight: bold;
			color: gray;
			color: hsla(203,20%,40%,.7);
		}
		body.toc-sidebar #toc-jump:not(:focus) {
			width: 0;
			height: 0;
			padding: 0;
			position: absolute;
			overflow: hidden;
		}
	}
	/* Hide main scroller when only the ToC is visible anyway */
	@media screen and (max-width: 28em) {
		body.toc-sidebar {
			overflow: hidden;
		}
	}

	/* Sidebar with its own space */
	@media screen and (min-width: 78em) {
		body:not(.toc-inline) #toc {
			position: fixed;
			top: 0; bottom: 0;
			left: 0;
			width: 23.5em;
			overflow: auto;
			padding: 0 1em;
			padding-left: 42px;
			padding-left: calc(1em + 26px);
			background: inherit;
			background-color: #f7f8f9;
			z-index: 1;
			box-shadow: -.1em 0 .25em rgba(0,0,0,.1) inset;
		}
		body:not(.toc-inline) #toc h2 {
			margin-top: .8rem;
			font-variant: small-caps;
			font-variant: all-small-caps;
			text-transform: lowercase;
			font-weight: bold;
			color: gray;
			color: hsla(203,20%,40%,.7);
		}

		body:not(.toc-inline) {
			padding-left: 29em;
		}
		/* See also Overflow section at the bottom */

		body:not(.toc-inline) #toc-jump:not(:focus) {
			width: 0;
			height: 0;
			padding: 0;
			position: absolute;
			overflow: hidden;
		}
	}
	@media screen and (min-width: 90em) {
		body:not(.toc-inline) {
			margin: 0 4em;
		}
	}

/******************************************************************************/
/*                                Sectioning                                  */
/******************************************************************************/

/** Headings ******************************************************************/

	h1, h2, h3, h4, h5, h6, dt {
		page-break-after: avoid;
		page-break-inside: avoid;
		font: 100% sans-serif;   /* Reset all font styling to clear out UA styles */
		font-family: inherit;    /* Inherit the font family. */
		line-height: 1.2;        /* Keep wrapped headings compact */
		hyphens: manual;         /* Hyphenated headings look weird */
	}

	h2, h3, h4, h5, h6 {
		margin-top: 3rem;
	}

	h1, h2, h3 {
		color: #005A9C;
		background: transparent;
	}

	h1 { font-size: 170%; }
	h2 { font-size: 140%; }
	h3 { font-size: 120%; }
	h4 { font-weight: bold; }
	h5 { font-style: italic; }
	h6 { font-variant: small-caps; }
	dt { font-weight: bold; }

/** Subheadings ***************************************************************/

	h1 + h2,
	#subtitle {
		/* #subtitle is a subtitle in an H2 under the H1 */
		margin-top: 0;
	}
	h2 + h3,
	h3 + h4,
	h4 + h5,
	h5 + h6 {
		margin-top: 1.2em; /* = 1 x line-height */
	}

/** Section divider ***********************************************************/

	:not(.head) > hr {
		font-size: 1.5em;
		text-align: center;
		margin: 1em auto;
		height: auto;
		border: transparent solid 0;
		background: transparent;
	}
	:not(.head) > hr::before {
		content: "\2727\2003\2003\2727\2003\2003\2727";
	}

/******************************************************************************/
/*                            Paragraphs and Lists                            */
/******************************************************************************/

	p {
		margin: 1em 0;
	}

	dd > p:first-child,
	li > p:first-child {
		margin-top: 0;
	}

	ul, ol {
		margin-left: 0;
		padding-left: 2em;
	}

	li {
		margin: 0.25em 0 0.5em;
		padding: 0;
	}

	dl dd {
		margin: 0 0 .5em 2em;
	}

	.head dd + dd { /* compact for header */
		margin-top: -.5em;
	}

	/* Style for algorithms */
	ol.algorithm ol:not(.algorithm),
	.algorithm > ol ol:not(.algorithm) {
	 border-left: 0.5em solid #DEF;
	}

	/* Put nice boxes around each algorithm. */
	[data-algorithm]:not(.heading) {
	  padding: .5em;
	  border: thin solid #ddd; border-radius: .5em;
	  margin: .5em calc(-0.5em - 1px);
	}
	[data-algorithm]:not(.heading) > :first-child {
	  margin-top: 0;
	}
	[data-algorithm]:not(.heading) > :last-child {
	  margin-bottom: 0;
	}

	/* Style for switch/case <dl>s */
	dl.switch > dd > ol.only,
	dl.switch > dd > .only > ol {
	 margin-left: 0;
	}
	dl.switch > dd > ol.algorithm,
	dl.switch > dd > .algorithm > ol {
	 margin-left: -2em;
	}
	dl.switch {
	 padding-left: 2em;
	}
	dl.switch > dt {
	 text-indent: -1.5em;
	 margin-top: 1em;
	}
	dl.switch > dt + dt {
	 margin-top: 0;
	}
	dl.switch > dt::before {
	 content: '\21AA';
	 padding: 0 0.5em 0 0;
	 display: inline-block;
	 width: 1em;
	 text-align: right;
	 line-height: 0.5em;
	}

/** Terminology Markup ********************************************************/


/******************************************************************************/
/*                                 Inline Markup                              */
/******************************************************************************/

/** Terminology Markup ********************************************************/
	dfn   { /* Defining instance */
		font-weight: bolder;
	}
	a > i { /* Instance of term */
		font-style: normal;
	}
	dt dfn code, code.idl {
		font-size: medium;
	}
	dfn var {
		font-style: normal;
	}

/** Change Marking ************************************************************/

	del { color: red;  text-decoration: line-through; }
	ins { color: #080; text-decoration: underline;    }

/** Miscellaneous improvements to inline formatting ***************************/

	sup {
		vertical-align: super;
		font-size: 80%
	}

/******************************************************************************/
/*                                    Code                                    */
/******************************************************************************/

/** General monospace/pre rules ***********************************************/

	pre, code, samp {
		font-family: Menlo, Consolas, "DejaVu Sans Mono", Monaco, monospace;
		font-size: .9em;
		page-break-inside: avoid;
		hyphens: none;
		text-transform: none;
	}
	pre code,
	code code {
		font-size: 100%;
	}

	pre {
		margin-top: 1em;
		margin-bottom: 1em;
		overflow: auto;
	}

/** Inline Code fragments *****************************************************/

  /* Do something nice. */

/******************************************************************************/
/*                                    Links                                   */
/******************************************************************************/

/** General Hyperlinks ********************************************************/

	/* We hyperlink a lot, so make it less intrusive */
	a[href] {
		color: #034575;
		text-decoration: none;
		border-bottom: 1px solid #707070;
		/* Need a bit of extending for it to look okay */
		padding: 0 1px 0;
		margin: 0 -1px 0;
	}
	a:visited {
		border-bottom-color: #BBB;
	}

	/* Use distinguishing colors when user is interacting with the link */
	a[href]:focus,
	a[href]:hover {
		background: #f8f8f8;
		background: rgba(75%, 75%, 75%, .25);
		border-bottom-width: 3px;
		margin-bottom: -2px;
	}
	a[href]:active {
		color: #C00;
		border-color: #C00;
	}

	/* Backout above styling for W3C logo */
	.head .logo,
	.head .logo a {
		border: none;
		text-decoration: none;
		background: transparent;
	}

/******************************************************************************/
/*                                    Images                                  */
/******************************************************************************/

	img {
		border-style: none;
	}

	/* For autogen numbers, add
	   .caption::before, figcaption::before { content: "Figure " counter(figure) ". "; }
	*/

	figure, .figure, .sidefigure {
		page-break-inside: avoid;
		text-align: center;
		margin: 2.5em 0;
	}
	.figure img,    .sidefigure img,    figure img,
	.figure object, .sidefigure object, figure object {
		max-width: 100%;
		margin: auto;
	}
	.figure pre, .sidefigure pre, figure pre {
		text-align: left;
		display: table;
		margin: 1em auto;
	}
	.figure table, figure table {
		margin: auto;
	}
	@media screen and (min-width: 20em) {
		.sidefigure {
			float: right;
			width: 50%;
			margin: 0 0 0.5em 0.5em
		}
	}
	.caption, figcaption, caption {
		font-style: italic;
		font-size: 90%;
	}
	.caption::before, figcaption::before, figcaption > .marker {
		font-weight: bold;
	}
	.caption, figcaption {
		counter-increment: figure;
	}

	/* DL list is indented 2em, but figure inside it is not */
	dd > .figure, dd > figure { margin-left: -2em }

/******************************************************************************/
/*                             Colored Boxes                                  */
/******************************************************************************/

	.issue, .note, .example, .assertion, .advisement, blockquote {
		padding: .5em;
		border: .5em;
		border-left-style: solid;
		page-break-inside: avoid;
	}
	span.issue, span.note {
		padding: .1em .5em .15em;
		border-right-style: solid;
	}

	.issue,
	.note,
	.example,
	.advisement,
	.assertion,
	blockquote {
		margin: 1em auto;
	}
	.note  > p:first-child,
	.issue > p:first-child,
	blockquote > :first-child {
		margin-top: 0;
	}
	blockquote > :last-child {
		margin-bottom: 0;
	}

/** Blockquotes ***************************************************************/

	blockquote {
		border-color: silver;
	}

/** Open issue ****************************************************************/

	.issue {
		border-color: #E05252;
		background: #FBE9E9;
		counter-increment: issue;
		overflow: auto;
	}
	.issue::before, .issue > .marker {
		text-transform: uppercase;
		color: #AE1E1E;
		padding-right: 1em;
		text-transform: uppercase;
	}
	/* Add .issue::before { content: "Issue " counter(issue) " "; } for autogen numbers,
	   or use class="marker" to mark up the issue number in source. */

/** Example *******************************************************************/

	.example {
		border-color: #E0CB52;
		background: #FCFAEE;
		counter-increment: example;
		overflow: auto;
		clear: both;
	}
	.example::before, .example > .marker {
		text-transform: uppercase;
		color: #827017;
		min-width: 7.5em;
		display: block;
	}
	/* Add .example::before { content: "Example " counter(example) " "; } for autogen numbers,
	   or use class="marker" to mark up the example number in source. */

/** Non-normative Note ********************************************************/

	.note {
		border-color: #52E052;
		background: #E9FBE9;
		overflow: auto;
	}

	.note::before, .note > .marker,
	details.note > summary::before,
	details.note > summary > .marker {
		text-transform: uppercase;
		display: block;
		color: hsl(120, 70%, 30%);
	}
	/* Add .note::before { content: "Note"; } for autogen label,
	   or use class="marker" to mark up the label in source. */

	details.note > summary {
		display: block;
		color: hsl(120, 70%, 30%);
	}
	details.note[open] > summary {
		border-bottom: 1px silver solid;
	}

/** Assertion Box *************************************************************/
	/*  for assertions in algorithms */

	.assertion {
		border-color: #AAA;
		background: #EEE;
	}

/** Advisement Box ************************************************************/
	/*  for attention-grabbing normative statements */

	.advisement {
		border-color: orange;
		border-style: none solid;
		background: #FFEECC;
	}
	strong.advisement {
		display: block;
		text-align: center;
	}
	.advisement > .marker {
		color: #B35F00;
	}

/** Spec Obsoletion Notice ****************************************************/
	/* obnoxious obsoletion notice for older/abandoned specs. */

	details {
		display: block;
	}
	summary {
		font-weight: bolder;
	}

	.annoying-warning:not(details),
	details.annoying-warning:not([open]) > summary,
	details.annoying-warning[open] {
		background: #fdd;
		color: red;
		font-weight: bold;
		padding: .75em 1em;
		border: thick red;
		border-style: solid;
		border-radius: 1em;
	}
	.annoying-warning :last-child {
		margin-bottom: 0;
	}

@media not print {
	details.annoying-warning[open] {
		position: fixed;
		left: 1em;
		right: 1em;
		bottom: 1em;
		z-index: 1000;
	}
}

	details.annoying-warning:not([open]) > summary {
		text-align: center;
	}

/** Entity Definition Boxes ***************************************************/

	.def {
		padding: .5em 1em;
		background: #DEF;
		margin: 1.2em 0;
		border-left: 0.5em solid #8CCBF2;
	}

/******************************************************************************/
/*                                    Tables                                  */
/******************************************************************************/

	th, td {
		text-align: left;
		text-align: start;
	}

/** Property/Descriptor Definition Tables *************************************/

	table.def {
		/* inherits .def box styling, see above */
		width: 100%;
		border-spacing: 0;
	}

	table.def td,
	table.def th {
		padding: 0.5em;
		vertical-align: baseline;
		border-bottom: 1px solid #bbd7e9;
	}

	table.def > tbody > tr:last-child th,
	table.def > tbody > tr:last-child td {
		border-bottom: 0;
	}

	table.def th {
		font-style: italic;
		font-weight: normal;
		padding-left: 1em;
		width: 3em;
	}

	/* For when values are extra-complex and need formatting for readability */
	table td.pre {
		white-space: pre-wrap;
	}

	/* A footnote at the bottom of a def table */
	table.def           td.footnote {
		padding-top: 0.6em;
	}
	table.def           td.footnote::before {
		content: " ";
		display: block;
		height: 0.6em;
		width: 4em;
		border-top: thin solid;
	}

/** Data tables (and properly marked-up index tables) *************************/
	/*
		 <table class="data"> highlights structural relationships in a table
		 when correct markup is used (e.g. thead/tbody, th vs. td, scope attribute)

		 Use class="complex data" for particularly complicated tables --
		 (This will draw more lines: busier, but clearer.)

		 Use class="long" on table cells with paragraph-like contents
		 (This will adjust text alignment accordingly.)
		 Alternately use class="longlastcol" on tables, to have the last column assume "long".
	*/

	table {
		word-wrap: normal;
		overflow-wrap: normal;
		hyphens: manual;
	}

	table.data,
	table.index {
		margin: 1em auto;
		border-collapse: collapse;
		border: hidden;
		width: 100%;
	}
	table.data caption,
	table.index caption {
		max-width: 50em;
		margin: 0 auto 1em;
	}

	table.data td,  table.data th,
	table.index td, table.index th {
		padding: 0.5em 1em;
		border-width: 1px;
		border-color: silver;
		border-top-style: solid;
	}

	table.data thead td:empty {
		padding: 0;
		border: 0;
	}

	table.data  thead,
	table.index thead,
	table.data  tbody,
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 <body class="h-entry">
  <div class="head">
   <p data-fill-with="logo"></p>
   <h1 class="p-name no-ref" id="title">P1135R3<br>The C++20 Synchronization Library</h1>
   <h2 class="no-num no-toc no-ref heading settled" id="subtitle"><span class="content">Published Proposal, <time class="dt-updated" datetime="2019-01-21">2019-01-21</time></span></h2>
   <div data-fill-with="spec-metadata">
    <dl>
     <dt>Authors:
     <dd>
      <dd class="editor p-author h-card vcard"><a class="p-name fn u-email email" href="mailto:brycelelbach@gmail.com">Bryce Adelstein Lelbach</a> (<span class="p-org org">NVIDIA</span>)
     <dd>
      <dd class="editor p-author h-card vcard"><a class="p-name fn u-email email" href="mailto:ogiroux@nvidia.com">Olivier Giroux</a> (<span class="p-org org">NVIDIA</span>)
     <dd>
      <dd class="editor p-author h-card vcard"><a class="p-name fn u-email email" href="mailto:jfbastien@apple.com">JF Bastien</a> (<span class="p-org org">Apple</span>)
     <dd>
      <dd class="editor p-author h-card vcard"><a class="p-name fn u-email email" href="mailto:dv@vollmann.ch">Detlef Vollmann</a>
     <dt>Source:
     <dd><a href="https://github.com/brycelelbach/wg21_p1135_cpp20_synchronization_library/blob/master/cpp20_synchronization_library.bs">GitHub</a>
     <dt>Issue Tracking:
     <dd><a href="https://github.com/brycelelbach/wg21_p1135_cpp20_synchronization_library/issues">GitHub</a>
     <dt>Project:
     <dd>ISO/IEC JTC1/SC22/WG21 14882: Programming Language — C++
     <dt>Audience:
     <dd>LWG
    </dl>
   </div>
   <div data-fill-with="warning"></div>
   <hr title="Separator for header">
  </div>
  <nav data-fill-with="table-of-contents" id="toc">
   <h2 class="no-num no-toc no-ref" id="contents">Table of Contents</h2>
   <ol class="toc" role="directory">
    <li><a href="#intro"><span class="secno">1</span> <span class="content">Introduction</span></a>
    <li><a href="#changelog"><span class="secno">2</span> <span class="content">Changelog</span></a>
    <li><a href="#wording"><span class="secno">3</span> <span class="content">Wording</span></a>
    <li>
     <a href="#index"><span class="secno"></span> <span class="content">Index</span></a>
     <ol class="toc">
      <li><a href="#index-defined-here"><span class="secno"></span> <span class="content">Terms defined by this specification</span></a>
     </ol>
    <li>
     <a href="#references"><span class="secno"></span> <span class="content">References</span></a>
     <ol class="toc">
      <li><a href="#informative"><span class="secno"></span> <span class="content">Informative References</span></a>
     </ol>
   </ol>
  </nav>
  <main>
   <h2 class="heading settled" data-level="1" id="intro"><span class="secno">1. </span><span class="content">Introduction</span><a class="self-link" href="#intro"></a></h2>
   <p>This paper is the unification of a series of related C++20 proposals for
introducing new synchronization and thread coordination facilities and
enhancing existing ones:</p>
   <ul>
    <li data-md>
     <p><a data-link-type="biblio" href="#biblio-p0514r4">[P0514R4]</a>: Efficient <code class="highlight"><c- n>atomic</c-></code> waiting and semaphores.</p>
    <li data-md>
     <p><a data-link-type="biblio" href="#biblio-p0666r2">[P0666R2]</a>: Latches and barriers.</p>
    <li data-md>
     <p><a data-link-type="biblio" href="#biblio-p0995r1">[P0995R1]</a>: <code class="highlight"><c- n>atomic_flag</c-><c- o>::</c-><c- n>test</c-></code> and lockfree integral types.</p>
    <li data-md>
     <p><a data-link-type="biblio" href="#biblio-p1258r0">[P1258R0]</a>: Don’t make C++ unimplementable for small CPUs.</p>
   </ul>
   <h2 class="heading settled" data-level="2" id="changelog"><span class="secno">2. </span><span class="content">Changelog</span><a class="self-link" href="#changelog"></a></h2>
   <p><strong>Revision 0:</strong> Post Rapperswil 2018 changes from <a data-link-type="biblio" href="#biblio-p0514r4">[P0514R4]</a>, <a data-link-type="biblio" href="#biblio-p0666r2">[P0666R2]</a>, and <a data-link-type="biblio" href="#biblio-p0995r1">[P0995R1]</a> based on <a href="http://wiki.edg.com/bin/view/Wg21rapperswil2018/P0666">Rapperswil 2018 LEWG feedback</a>.</p>
   <ul>
    <li data-md>
     <p>Refactored <code class="highlight"><c- n>basic_barrier</c-></code> and <code class="highlight"><c- n>barrier</c-></code> into one class with a default template parameter as suggested by LEWG at Rapperswil 2018.</p>
    <li data-md>
     <p>Refactored <code class="highlight"><c- n>basic_semaphore</c-></code> and <code class="highlight"><c- n>counting_semaphore</c-></code> into one class with a default template parameter as suggested by LEWG at Rapperswil 2018.</p>
    <li data-md>
     <p>Fixed <code class="highlight"><c- n>update</c-></code> parameters in semaphore, latch, and barrier member functions to consistently default to 1 to resolve mistakes identified by LEWG at Rapperswil 2018.</p>
   </ul>
   <p><strong>Revision 1:</strong> Pre San Diego 2018 changes based on <a href="http://wiki.edg.com/bin/view/Wg21rapperswil2018/P0666">Rapperswil 2018 LEWG feedback</a> and <a href="http://lists.isocpp.org/lib-ext/2018/06/7755.php">a June discussion on the LEWG and SG1 mailing lists</a>.</p>
   <ul>
    <li data-md>
     <p>Added member function versions of <code class="highlight"><c- n>atomic_wait_</c-><c- o>*</c-></code> and <code class="highlight"><c- n>atomic_notify_</c-><c- o>*</c-></code>, for consistency. Refactored wording to accommodate this.</p>
    <li data-md>
     <p>Renamed the <code class="highlight"><c- n>atomic_flag</c-></code> overloads of <code class="highlight"><c- n>atomic_wait</c-></code> and <code class="highlight"><c- n>atomic_wait_explicit</c-></code> to <code class="highlight"><c- n>atomic_flag_wait</c-></code> and <code class="highlight"><c- n>atomic_flag_wait_explicit</c-></code> for consistency and to leave the door open for future compatibility with C.</p>
    <li data-md>
     <p>Renamed <code class="highlight"><c- n>latch</c-><c- o>::</c-><c- n>arrive_and_wait</c-></code> and <code class="highlight"><c- n>barrier</c-><c- o>::</c-><c- n>arrive_and_wait</c-></code> to <code class="highlight"><c- n>latch</c-><c- o>::</c-><c- n>sync</c-></code> and <code class="highlight"><c- n>barrier</c-><c- o>::</c-><c- n>sync</c-></code>, because LEWG at Rapperswil 2018 expected these methods to be the common use case and prefers they have a short name.</p>
    <li data-md>
     <p>Renamed <code class="highlight"><c- n>latch</c-><c- o>::</c-><c- n>arrive</c-></code> to <code class="highlight"><c- n>latch</c-><c- o>::</c-><c- n>count_down</c-></code> to further separate and distinguish the <code class="highlight"><c- n>latch</c-></code> and <code class="highlight"><c- n>barrier</c-></code> interfaces.</p>
    <li data-md>
     <p>Removed <code class="highlight"><c- n>barrier</c-><c- o>::</c-><c- n>try_wait</c-></code> to resolve concerns raised during LEWG discussion at Rapperswil 2018 regarding its "maybe consuming" nature.</p>
    <li data-md>
     <p>Required that <code class="highlight"><c- n>barrier</c-><c- o>::</c-><c- n>arrival_token</c-></code>'s move constructor and move assignment operators are <code class="highlight"><c- k>noexcept</c-></code> to resolve discussions in LEWG at Rapperswil 2018 regarding exceptions being thrown when using the split arrive and wait barrier interface.</p>
    <li data-md>
     <p>Made <code class="highlight"><c- n>counting_semaphore</c-><c- o>::</c-><c- n>acquire</c-></code>, <code class="highlight"><c- n>counting_semaphore</c-><c- o>::</c-><c- n>try_acquire</c-></code>, and <code class="highlight"><c- n>latch</c-><c- o>::</c-><c- n>wait</c-></code> <code class="highlight"><c- k>noexcept</c-></code>, because participants in the mailing list discussion preferred that synchronization operations not throw and that any resource acquisition failures be reported by throwing during construction of synchronization objects.</p>
    <li data-md>
     <p>Made <code class="highlight"><c- n>counting_semaphore</c-></code>, <code class="highlight"><c- n>latch</c-></code>, and <code class="highlight"><c- n>barrier</c-></code>'s constructors non <code class="highlight"><c- k>constexpr</c-></code> and allowed them to throw <code class="highlight"><c- n>system_error</c-></code> if the object cannot be created, because participants in the mailing list discussion preferred that synchronization operations not throw and that any resource acquisition failures be reported by throwing during construction of synchronization objects.</p>
    <li data-md>
     <p>Clarified that <code class="highlight"><c- n>counting_semaphore</c-><c- o>::</c-><c- n>release</c-></code>, <code class="highlight"><c- n>latch</c-><c- o>::</c-><c- n>count_down</c-></code>, <code class="highlight"><c- n>latch</c-><c- o>::</c-><c- n>sync</c-></code>, <code class="highlight"><c- n>barrier</c-><c- o>::</c-><c- n>wait</c-></code>, <code class="highlight"><c- n>barrier</c-><c- o>::</c-><c- n>sync</c-></code>, and <code class="highlight"><c- n>barrier</c-><c- o>::</c-><c- n>arrive_and_drop</c-></code> throw nothing (but cannot be <code class="highlight"><c- k>noexcept</c-></code>, because they have preconditions) to resolve discussions in LEWG at Rapperswil 2018 and on the mailing list.</p>
   </ul>
   <p><strong>Revision 2:</strong> San Diego 2018 changes to incorporate <a data-link-type="biblio" href="#biblio-p1258r0">[P1258R0]</a> and pre-meeting feedback.</p>
   <ul>
    <li data-md>
     <p>Made <code class="highlight"><c- n>barrier</c-><c- o>::</c-><c- n>wait</c-></code> take its <code class="highlight"><c- n>arrival_token</c-></code> parameter by rvalue reference.</p>
    <li data-md>
     <p>Made the <code class="highlight"><c- n>atomic_signed_lock_free</c-></code> and <code class="highlight"><c- n>atomic_unsigned_lock_free</c-></code> types optional for freestanding implementations, as per <a data-link-type="biblio" href="#biblio-p1258r0">[P1258R0]</a>.</p>
   </ul>
   <p><strong>Revision 3:</strong> Pre Kona 2019 changes based on <a href="http://wiki.edg.com/bin/view/Wg21sandiego2018/P1135">San Diego 2018 LEWG feedback</a>.</p>
   <ul>
    <li data-md>
     <p>Renamed <code class="highlight"><c- n>latch</c-><c- o>::</c-><c- n>sync</c-></code> and <code class="highlight"><c- n>barrier</c-><c- o>::</c-><c- n>sync</c-></code> back to <code class="highlight"><c- n>latch</c-><c- o>::</c-><c- n>arrive_and_wait</c-></code> and <code class="highlight"><c- n>barrier</c-><c- o>::</c-><c- n>arrive_and_wait</c-></code>, because this name had the strongest consensus in LEWG at San Diego 2018.</p>
    <li data-md>
     <p>Removed <code class="highlight"><c- n>atomic_int_fast_wait_t</c-></code> and <code class="highlight"><c- n>atomic_uint_fast_wait_t</c-></code>, because LEWG at San Diego 2018 felt that the use case was uncommon and the types had high potential for misuse.</p>
    <li data-md>
     <p>Made <code class="highlight"><c- n>counting_semaphore</c-><c- o>::</c-><c- n>acquire</c-></code> and <code class="highlight"><c- n>latch</c-><c- o>::</c-><c- n>wait</c-></code> non <code class="highlight"><c- k>noexcept</c-></code> again, because LEWG at San Diego 2018 desired <code class="highlight"><c- k>constexpr</c-></code> constructors for new synchronization objects to allow synchronization during program initialization and to maintain consistency with existing synchronization objects like <code class="highlight"><c- n>mutex</c-></code>.</p>
    <li data-md>
     <p>Made <code class="highlight"><c- n>counting_semaphore</c-></code>, <code class="highlight"><c- n>latch</c-></code>, and <code class="highlight"><c- n>barrier</c-></code>'s constructors <code class="highlight"><c- k>constexpr</c-></code> again, because LEWG at San Diego 2018 desired <code class="highlight"><c- k>constexpr</c-></code> constructors for new synchronization objects to allow synchronization during program initialization and to maintain consistency with existing synchronization objects like <code class="highlight"><c- n>mutex</c-></code>.</p>
    <li data-md>
     <p>Clarified that <code class="highlight"><c- n>counting_semaphore</c-><c- o>::</c-><c- n>release</c-></code>, <code class="highlight"><c- n>latch</c-><c- o>::</c-><c- n>count_down</c-></code>, <code class="highlight"><c- n>latch</c-><c- o>::</c-><c- n>arrive_and_wait</c-></code>, <code class="highlight"><c- n>barrier</c-><c- o>::</c-><c- n>wait</c-></code>, <code class="highlight"><c- n>barrier</c-><c- o>::</c-><c- n>arrive_and_wait</c-></code>, and <code class="highlight"><c- n>barrier</c-><c- o>::</c-><c- n>arrive_and_drop</c-></code> may throw <code class="highlight"><c- n>system_error</c-></code> exceptions, which is an implication of the constructors of said objects being <code class="highlight"><c- k>constexpr</c-></code> because any underlying system errors must be reported on operations not during construction.</p>
    <li data-md>
     <p>Added missing <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>::</c-><c- n>wait</c-></code> and <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>::</c-><c- n>notify_</c-><c- o>*</c-></code> member functions to the class synopses for the <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> integral, floating-point, and pointer specializations.</p>
    <li data-md>
     <p>Fixed <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>::</c-><c- n>notify_</c-><c- o>*</c-></code> member functions to be non <code class="highlight"><c- k>const</c-></code>.</p>
   </ul>
   <h2 class="heading settled" data-level="3" id="wording"><span class="secno">3. </span><span class="content">Wording</span><a class="self-link" href="#wording"></a></h2>
   <p class="note" role="note"><span>Note:</span> The following changes are relative to the post San Diego 2018 working draft of ISO/IEC 14882, (<a data-link-type="biblio" href="#biblio-n4791">[N4791]</a>).</p>
   <p class="note" role="note"><span>Note:</span> The � character is used to denote a placeholder number which shall be selected by the editor.</p>
   <p>Add <code class="highlight"><c- o>&lt;</c-><c- n>semaphore</c-><c- o>></c-></code>, <code class="highlight"><c- o>&lt;</c-><c- n>latch</c-><c- o>></c-></code>, and <code class="highlight"><c- o>&lt;</c-><c- n>barrier</c-><c- o>></c-></code> to Table 19 "C++ library headers" in <a href="http://eel.is/c++draft/headers">[<strong>headers</strong>]</a>.</p>
   <p>Modify the header synopsis for <code class="highlight"><c- o>&lt;</c-><c- n>atomic</c-><c- o>></c-></code> in <a href="http://eel.is/c++draft/atomics.syn">[<strong>atomics.syn</strong>]</a> as follows:</p>
   <blockquote>
     <b>30.2 Header <code class="highlight"><c- o>&lt;</c-><c- n>atomic</c-><c- o>></c-></code> synopsis <span style="float: right;">[atomics.syn]</span></b> 
<pre class="highlight"><code class="highlight"><c- k><c- k>namespace</c-></c-> <c- n><c- n>std</c-></c-> <c- p><c- p>{</c-></c->
  <i><c- c1><c- c1>// ...</c-></c-></i>
  
  <i><c- c1><c- c1>// 30.8, non-member functions</c-></c-></i>
  <i><c- c1><c- c1>// ...</c-></c-></i>
</code></pre>
<pre class="ins highlight"><code class="highlight">  <c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>class</c-></c-> <c- nc><c- nc>T</c-></c-><c- o><c- o>></c-></c-> </code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- n><c- n>atomic_wait</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>>*</c-></c-><c- p><c- p>,</c-></c-> </code></pre>
<pre class="ins highlight"><code class="highlight">                     <c- k><c- k>typename</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>>::</c-></c-><c- n><c- n>value_type</c-></c-><c- p><c- p>);</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>class</c-></c-> <c- nc><c- nc>T</c-></c-><c- o><c- o>></c-></c-> </code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- n><c- n>atomic_wait</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>>*</c-></c-><c- p><c- p>,</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">                     <c- k><c- k>typename</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>>::</c-></c-><c- n><c- n>value_type</c-></c-><c- p><c- p>);</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>class</c-></c-> <c- nc><c- nc>T</c-></c-><c- o><c- o>></c-></c-> </code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- n><c- n>atomic_wait_explicit</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>>*</c-></c-><c- p><c- p>,</c-></c-> </code></pre>
<pre class="ins highlight"><code class="highlight">                              <c- k><c- k>typename</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>>::</c-></c-><c- n><c- n>value_type</c-></c-><c- p><c- p>,</c-></c-> </code></pre>
<pre class="ins highlight"><code class="highlight">                              <c- n><c- n>memory_order</c-></c-><c- p><c- p>);</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>class</c-></c-> <c- nc><c- nc>T</c-></c-><c- o><c- o>></c-></c-> </code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- n><c- n>atomic_wait_explicit</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>>*</c-></c-><c- p><c- p>,</c-></c-> </code></pre>
<pre class="ins highlight"><code class="highlight">                              <c- k><c- k>typename</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>>::</c-></c-><c- n><c- n>value_type</c-></c-><c- p><c- p>,</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">                              <c- n><c- n>memory_order</c-></c-><c- p><c- p>);</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>class</c-></c-> <c- nc><c- nc>T</c-></c-><c- o><c- o>></c-></c-> </code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_notify_one</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>>*</c-></c-><c- p><c- p>);</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>class</c-></c-> <c- nc><c- nc>T</c-></c-><c- o><c- o>></c-></c-> </code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_notify_one</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>atomic</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>>*</c-></c-><c- p><c- p>);</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_notify_one</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>);</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_notify_one</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>);</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>class</c-></c-> <c- nc><c- nc>T</c-></c-><c- o><c- o>></c-></c-> </code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_notify_all</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>>*</c-></c-><c- p><c- p>);</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>class</c-></c-> <c- nc><c- nc>T</c-></c-><c- o><c- o>></c-></c-> </code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_notify_all</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>atomic</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>>*</c-></c-><c- p><c- p>);</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_notify_all</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>);</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_notify_all</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>);</c-></c-></code></pre>
<pre class="highlight"> 
  <i><c- c1>// 30.3, type aliases</c-></i>
  <i><c- c1>// ...</c-></i>
   
  <c- k>using</c-> <c- n>atomic_intptr_t</c->       <c- o>=</c-> <c- n>atomic</c-><c- o>&lt;</c-><c- b>intptr_t</c-><c- o>></c-><c- p>;</c->
  <c- k>using</c-> <c- n>atomic_uintptr_t</c->      <c- o>=</c-> <c- n>atomic</c-><c- o>&lt;</c-><c- b>uintptr_t</c-><c- o>></c-><c- p>;</c->
  <c- k>using</c-> <c- n>atomic_size_t</c->         <c- o>=</c-> <c- n>atomic</c-><c- o>&lt;</c-><c- b>size_t</c-><c- o>></c-><c- p>;</c->
  <c- k>using</c-> <c- n>atomic_ptrdiff_t</c->      <c- o>=</c-> <c- n>atomic</c-><c- o>&lt;</c-><c- b>ptrdiff_t</c-><c- o>></c-><c- p>;</c->
  <c- k>using</c-> <c- n>atomic_intmax_t</c->       <c- o>=</c-> <c- n>atomic</c-><c- o>&lt;</c-><c- b>intmax_t</c-><c- o>></c-><c- p>;</c->
  <c- k>using</c-> <c- n>atomic_uintmax_t</c->      <c- o>=</c-> <c- n>atomic</c-><c- o>&lt;</c-><c- b>uintmax_t</c-><c- o>></c-><c- p>;</c->
 
</pre>
<pre class="ins highlight"><code class="highlight">  <c- k><c- k>using</c-></c-> <c- n><c- n>atomic_signed_lock_free</c-></c->   <c- o><c- o>=</c-></c-> <i><c- n><c- n>see</c-></c-> <c- n><c- n>below</c-></c-></i><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- k><c- k>using</c-></c-> <c- n><c- n>atomic_unsigned_lock_free</c-></c-> <c- o><c- o>=</c-></c-> <i><c- n><c- n>see</c-></c-> <c- n><c- n>below</c-></c-></i><c- p><c- p>;</c-></c-></code></pre>
<pre class="highlight"><code class="highlight"> 
  <i><c- c1><c- c1>// ...</c-></c-></i>

  <i><c- c1><c- c1>// 30.9, flag type and operations</c-></c-></i>
  <c- k><c- k>struct</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- p><c- p>;</c-></c->
</code></pre>
    <ins>
<pre class="highlight">  <c- b>bool</c-> <c- nf>atomic_flag_test</c-><c- p>(</c-><c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
  <c- b>bool</c-> <c- nf>atomic_flag_test</c-><c- p>(</c-><c- n>atomic_flag</c-><c- o>*</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
  <c- b>bool</c-> <c- nf>atomic_flag_test_explicit</c-><c- p>(</c-><c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-><c- p>,</c-> <c- n>memory_order</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
  <c- b>bool</c-> <c- nf>atomic_flag_test_explicit</c-><c- p>(</c-><c- n>atomic_flag</c-><c- o>*</c-><c- p>,</c-> <c- n>memory_order</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
    </ins>
<pre class="highlight"><code class="highlight">  <c- b><c- b>bool</c-></c-> <c- n><c- n>atomic_flag_test_and_set</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- b><c- b>bool</c-></c-> <c- nf><c- nf>atomic_flag_test_and_set</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- b><c- b>bool</c-></c-> <c- nf><c- nf>atomic_flag_test_and_set_explicit</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- b><c- b>bool</c-></c-> <c- nf><c- nf>atomic_flag_test_and_set_explicit</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_flag_clear</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_flag_clear</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_flag_clear_explicit</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_flag_clear_explicit</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
</code></pre>
<pre class="ins highlight"><code class="highlight">  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_flag_wait</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- b><c- b>bool</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_flag_wait</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- b><c- b>bool</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_flag_wait_explicit</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- b><c- b>bool</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_flag_wait_explicit</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- b><c- b>bool</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_flag_notify_one</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_flag_notify_one</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_flag_notify_all</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_flag_notify_all</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="highlight"><code class="highlight">  #<c- n><c- n>define</c-></c-> <c- n><c- n>ATOMIC_FLAG_INIT</c-></c-> <i><c- n><c- n>see</c-></c-> <c- n><c- n>below</c-></c-></i>

  <i><c- c1><c- c1>// 30.10, fences</c-></c-></i>
  <c- k><c- k>extern</c-></c-> <c- s><c- s>"C"</c-></c-> <c- b><c- b>void</c-></c-> <c- n><c- n>atomic_thread_fence</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- k><c- k>extern</c-></c-> <c- s><c- s>"C"</c-></c-> <c- b><c- b>void</c-></c-> <c- n><c- n>atomic_signal_fence</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
<c- p><c- p>}</c-></c->
</code></pre>
   </blockquote>
   <p>Modify <a href="http://eel.is/c++draft/atomics.alias">[<strong>atomics.alias</strong>]</a> as follows:</p>
   <blockquote>
     <b>30.3 Type aliases <span style="float: right;">[atomics.alias]</span></b> 
    <div class="numbered"> The type aliases <code class="highlight"><c- n>atomic_intN_t</c-></code>, <code class="highlight"><c- n>atomic_uintN_t</c-></code>, <code class="highlight"><c- n>atomic_intptr_t</c-></code>, and <code class="highlight"><c- n>atomic_uintptr_t</c-></code> are defined if and only if <code class="highlight"><c- n>intN_t</c-></code>, <code class="highlight"><c- n>uintN_t</c-></code>, <code class="highlight"><c- b>intptr_t</c-></code>, and <code class="highlight"><c- b>uintptr_t</c-></code> are defined, respectively. </div>
    <div class="ins">
     <div class="numbered"> The type aliases <code class="highlight"><c- n>atomic_signed_lock_free</c-></code> and <code class="highlight"><c- n>atomic_unsigned_lock_free</c-></code> are defined to be specializations of <code class="highlight"><c- n>atomic</c-></code> whose template arguments are integral types, respectively signed and unsigned, other than <code class="highlight"><c- b>bool</c-></code>.
In <a href="http://eel.is/c++draft/intro.compliance#def:freestanding_implementation">freestanding implementations</a> (4.1), these aliases are optional. If an implementation provides a integral specialization of <code class="highlight"><c- n>atomic</c-></code> other than <code class="highlight"><c- b>bool</c-></code> for which <code class="highlight"><c- n>is_always_lock_free</c-></code> is true, it shall define <code class="highlight"><c- n>atomic_signed_lock_free</c-></code> and <code class="highlight"><c- n>atomic_unsigned_lock_free</c-></code>. Otherwise, they shall not be defined. <code class="highlight"><c- n>is_always_lock_free</c-></code> shall be <code class="highlight">true</code> for <code class="highlight"><c- n>atomic_signed_lock_free</c-></code> and <code class="highlight"><c- n>atomic_unsigned_lock_free</c-></code>.
An implementation which defines these type aliases should choose the integral specialization of <code class="highlight"><c- n>atomic</c-></code> for which the <a data-link-type="dfn" href="#atomic-waiting-and-notifying-operations" id="ref-for-atomic-waiting-and-notifying-operations">atomic waiting and notifying operations</a> are most efficient. </div>
    </div>
   </blockquote>
   <p class="note" role="note"><span>Note:</span> The reference to "<a data-link-type="dfn" href="#atomic-waiting-and-notifying-operations" id="ref-for-atomic-waiting-and-notifying-operations①">atomic waiting and notifying operations</a>" in the above change should refer to the new <a href="http://eel.is/c++draft/atomic.wait">[<strong>atomic.wait</strong>]</a> subclause.</p>
   <p>Add a new subclause after <a href="http://eel.is/c++draft/atomics.lockfree">[<strong>atomics.lockfree</strong>]</a>:</p>
   <blockquote class="ins">
     <b>30.� Waiting and notifying <span style="float: right;">[atomics.wait]</span></b> 
    <div class="numbered"> <dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="atomic-waiting-and-notifying-operations">Atomic waiting and notifying operations</dfn> provide a mechanism to wait for the value of an atomic object to change more efficiently than can be achieved with polling. </div>
    <div class="numbered">
      The following functions are <dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="atomic-waiting-operations">atomic waiting operations</dfn>: 
     <ul>
      <li data-md>
       <p><code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>::</c-><c- n>wait</c-></code>.</p>
      <li data-md>
       <p><code class="highlight"><c- n>atomic_flag</c-><c- o>::</c-><c- n>wait</c-></code>.</p>
      <li data-md>
       <p><code class="highlight"><c- n>atomic_wait</c-></code> and <code class="highlight"><c- n>atomic_wait_explicit</c-></code>.</p>
     </ul>
    </div>
    <div class="numbered">
      The following functions are <dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="atomic-notifying-operations">atomic notifying operations</dfn>: 
     <ul>
      <li data-md>
       <p><code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>::</c-><c- n>notify_one</c-></code> and <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>::</c-><c- n>notify_all</c-></code>.</p>
      <li data-md>
       <p><code class="highlight"><c- n>atomic_flag</c-><c- o>::</c-><c- n>notify_one</c-></code> and <code class="highlight"><c- n>atomic_flag</c-><c- o>::</c-><c- n>notify_all</c-></code>.</p>
      <li data-md>
       <p><code class="highlight"><c- n>atomic_notify_one</c-></code> and <code class="highlight"><c- n>atomic_notify_one_explicit</c-></code>.</p>
      <li data-md>
       <p><code class="highlight"><c- n>atomic_flag_notify_one</c-></code> and <code class="highlight"><c- n>atomic_flag_notify_one_explicit</c-></code>.</p>
      <li data-md>
       <p><code class="highlight"><c- n>atomic_notify_all</c-></code> and <code class="highlight"><c- n>atomic_notify_all_explicit</c-></code>.</p>
      <li data-md>
       <p><code class="highlight"><c- n>atomic_flag_notify_all</c-></code> and <code class="highlight"><c- n>atomic_flag_notify_all_explicit</c-></code>.</p>
     </ul>
    </div>
    <div class="numbered"> <a data-link-type="dfn" href="#atomic-waiting-operations" id="ref-for-atomic-waiting-operations">Atomic waiting operations</a> in this facility may block until they are unblocked by <a data-link-type="dfn" href="#atomic-notifying-operations" id="ref-for-atomic-notifying-operations">atomic notifying operations</a>, according to each function’s effects.
[ <em>Note:</em> Programs are not guaranteed to observe transient atomic values, an issue known as the A-B-A problem, resulting in continued blocking if a condition is only temporarily met. – <em>end note</em> ] </div>
   </blockquote>
   <p>Modify <a href="http://eel.is/c++draft/atomics.types.generic">[<strong>atomics.types.generic</strong>]</a> as follows:</p>
   <blockquote>
     <b>30.7 Class template <code class="highlight"><c- n>atomic</c-></code> <span style="float: right;">[atomics.types.generic]</span></b> 
<pre class="highlight"><code class="highlight"><c- k><c- k>namespace</c-></c-> <c- n><c- n>std</c-></c-> <c- p><c- p>{</c-></c->
  <c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>class</c-></c-> <c- nc><c- nc>T</c-></c-><c- o><c- o>></c-></c-> <c- k><c- k>struct</c-></c-> <c- n><c- n>atomic</c-></c-> <c- p><c- p>{</c-></c->
    <c- k><c- k>using</c-></c-> <c- n><c- n>value_type</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>T</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>static</c-></c-> <c- k><c- k>constexpr</c-></c-> <c- b><c- b>bool</c-></c-> <c- n><c- n>is_always_lock_free</c-></c-> <c- o><c- o>=</c-></c-> <i><c- n><c- n>implementation</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>defined</c-></c-></i><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>is_lock_free</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>is_lock_free</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>void</c-></c-> <c- nf><c- nf>store</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>void</c-></c-> <c- nf><c- nf>store</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-> <c- nf><c- nf>load</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-> <c- nf><c- nf>load</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>operator</c-></c-> <c- nf><c- nf>T</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>operator</c-></c-> <c- nf><c- nf>T</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-> <c- nf><c- nf>exchange</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-> <c- nf><c- nf>exchange</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_weak</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_weak</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_strong</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_strong</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_weak</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_weak</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_strong</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_strong</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
</code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>wait</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-> <c- n><c- n>old</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>wait</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-> <c- n><c- n>old</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_one</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_one</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_all</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_all</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="highlight"><code class="highlight">    <c- n><c- n>atomic</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>default</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>constexpr</c-></c-> <c- nf><c- nf>atomic</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>atomic</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- p><c- p>};</c-></c->
<c- p><c- p>}</c-></c->
</code></pre>
   </blockquote>
   <p>Add the following to the end of <a href="http://eel.is/c++draft/atomics.types.operations">[<strong>atomics.types.operations</strong>]</a>:</p>
   <blockquote class="ins">
<pre class="highlight"><c- b>void</c-> <c- nf>wait</c-><c- p>(</c-><c- n>T</c-> <c- n>old</c-><c- p>,</c-> <c- n>memory_order</c-> <c- n>order</c-> <c- o>=</c-> <c- n>memory_order</c-><c- o>::</c-><c- n>seq_cst</c-><c- p>)</c-> <c- k>const</c-> <c- k>volatile</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- nf>wait</c-><c- p>(</c-><c- n>T</c-> <c- n>old</c-><c- p>,</c-> <c- n>memory_order</c-> <c- n>order</c-> <c- o>=</c-> <c- n>memory_order</c-><c- o>::</c-><c- n>seq_cst</c-><c- p>)</c-> <c- k>const</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
    <div class="numbered"> <em>Requires:</em> The <code class="highlight"><c- n>order</c-></code> argument shall not be <code class="highlight"><c- n>memory_order_release</c-></code> nor <code class="highlight"><c- n>memory_order_acq_rel</c-></code>. </div>
    <div class="numbered">
      <em>Effects:</em> Repeatedly performs the following steps, in order: 
     <ul>
      <li data-md>
       <p>Evaluates <code class="highlight"><c- n>object</c-><c- o>-></c-><c- n>load</c-><c- p>(</c-><c- n>order</c-><c- p>)</c-> <c- o>!=</c-> <c- n>old</c-></code> then, if the result is <code class="highlight">true</code>, returns.</p>
      <li data-md>
       <p>Blocks until an implementation-defined condition has been met.
[ <em>Note:</em> Consequently, it may unblock for reasons other than an <a data-link-type="dfn" href="#atomic-notifying-operations" id="ref-for-atomic-notifying-operations①">atomic notifying operation</a>. — <em>end note</em> ]</p>
     </ul>
    </div>
    <div class="numbered"> <em>Remarks:</em> This function is an <a data-link-type="dfn" href="#atomic-waiting-operations" id="ref-for-atomic-waiting-operations①">atomic waiting operation</a>. </div>
<pre class="highlight"><c- b>void</c-> <c- nf>notify_one</c-><c- p>()</c-> <c- k>volatile</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- nf>notify_one</c-><c- p>()</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
    <div class="numbered"> <em>Effects:</em> Unblocks up to execution of an <a data-link-type="dfn" href="#atomic-waiting-operations" id="ref-for-atomic-waiting-operations②">atomic waiting operation</a> that blocked after observing the result of an atomic operation <code class="highlight"><c- n>X</c-></code>, if there exists another atomic operation <code class="highlight"><c- n>Y</c-></code>, such that <code class="highlight"><c- n>X</c-></code> precedes <code class="highlight"><c- n>Y</c-></code> in the modification order of <code class="highlight"><c- o>*</c-><c- k>this</c-></code>, and <code class="highlight"><c- n>Y</c-></code> happens before this call. </div>
    <div class="numbered"> <em>Remarks:</em> This function is an <a data-link-type="dfn" href="#atomic-notifying-operations" id="ref-for-atomic-notifying-operations②">atomic notifying operation</a>. </div>
<pre class="highlight"><c- b>void</c-> <c- nf>notify_all</c-><c- p>()</c-> <c- k>volatile</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- nf>notify_all</c-><c- p>()</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
    <div class="numbered"> <em>Effects:</em> Unblocks each execution of an <a data-link-type="dfn" href="#atomic-waiting-operations" id="ref-for-atomic-waiting-operations③">atomic waiting operation</a> that blocked after observing the result of an atomic operation <code class="highlight"><c- n>X</c-></code>, if there exists another atomic operation <code class="highlight"><c- n>Y</c-></code>, such that <code class="highlight"><c- n>X</c-></code> precedes <code class="highlight"><c- n>Y</c-></code> in the modification order of <code class="highlight"><c- o>*</c-><c- k>this</c-></code>, and <code class="highlight"><c- n>Y</c-></code> happens before this call. </div>
    <div class="numbered"> <em>Remarks:</em> This function is an <a data-link-type="dfn" href="#atomic-notifying-operations" id="ref-for-atomic-notifying-operations③">atomic notifying operation</a>. </div>
   </blockquote>
   <p>Modify <a href="http://eel.is/c++draft/atomics.types.int#1">[<strong>atomics.types.int</strong>] paragraph 1</a> as follows:</p>
   <blockquote>
     <b>30.7.2 Specializations for integers <span style="float: right;">[atomics.types.int]</span></b> 
    <div class="numbered"> There are specializations of the <code class="highlight"><c- n>atomic</c-></code> class template for the integral types <code class="highlight"><c- b>char</c-></code>, <code class="highlight"><c- b>signed</c-> <c- b>char</c-></code>, <code class="highlight"><c- b>unsigned</c-> <c- b>char</c-></code>, <code class="highlight"><c- b>short</c-></code>, <code class="highlight"><c- b>unsigned</c-> <c- b>short</c-></code>, <code class="highlight"><c- b>int</c-></code>, <code class="highlight"><c- b>unsigned</c-> <c- b>int</c-></code>, <code class="highlight"><c- b>long</c-></code>, <code class="highlight"><c- b>unsigned</c-> <c- b>long</c-></code>, <code class="highlight"><c- b>long</c-> <c- b>long</c-></code>, <code class="highlight"><c- b>unsigned</c-> <c- b>long</c-> <c- b>long</c-></code>, <code class="highlight"><c- n>char8_t</c-></code>, <code class="highlight"><c- b>char16_t</c-></code>, <code class="highlight"><c- b>char32_t</c-></code>, <code class="highlight"><c- b>wchar_t</c-></code>, and any other types needed by the typedefs in the header <code class="highlight"><c- o>&lt;</c-><c- n>cstdint</c-><c- o>></c-></code>.
For each such type <code class="highlight"><i><c- n>integral</c-></i></code>, the specialization <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><i><c- n>integral</c-></i><c- o>></c-></code> provides additional atomic operations appropriate to integral types.
[ <em>Note:</em> For the specialization <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- b>bool</c-><c- o>></c-></code>, see <a href="http://eel.is/c++draft/atomics.types.generic">30.7</a>. — <em>end note</em> ] </div>
<pre class="highlight"><code class="highlight"><c- k><c- k>namespace</c-></c-> <c- n><c- n>std</c-></c-> <c- p><c- p>{</c-></c->
  <c- k><c- k>template</c-></c-><c- o><c- o>&lt;></c-></c-> <c- k><c- k>struct</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&lt;</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- o><c- o>></c-></c-> <c- p><c- p>{</c-></c->
    <c- k><c- k>using</c-></c-> <c- n><c- n>value_type</c-></c-> <c- o><c- o>=</c-></c-> <i><c- n><c- n>integral</c-></c-></i><c- p><c- p>;</c-></c->
    <c- k><c- k>using</c-></c-> <c- n><c- n>difference_type</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>value_type</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>static</c-></c-> <c- k><c- k>constexpr</c-></c-> <c- b><c- b>bool</c-></c-> <c- n><c- n>is_always_lock_free</c-></c-> <c- o><c- o>=</c-></c-> <i><c- n><c- n>implementation</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>defined</c-></c-></i><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>is_lock_free</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>is_lock_free</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>void</c-></c-> <c- nf><c- nf>store</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>void</c-></c-> <c- nf><c- nf>store</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- nf><c- nf>load</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- nf><c- nf>load</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>operator</c-></c-> <i><c- nf><c- nf>integral</c-></c-></i><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>operator</c-></c-> <i><c- nf><c- nf>integral</c-></c-></i><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- nf><c- nf>exchange</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- nf><c- nf>exchange</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_weak</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c->
                               <c- n><c- n>memory_order</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_weak</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c->
                               <c- n><c- n>memory_order</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_strong</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c->
                                 <c- n><c- n>memory_order</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_strong</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c->
                                 <c- n><c- n>memory_order</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_weak</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c->
                               <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_weak</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c->
                               <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_strong</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c->
                                 <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_strong</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c->
                                 <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
</code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>wait</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i> <c- n><c- n>old</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>wait</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i> <c- n><c- n>old</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_one</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_one</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_all</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_all</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="highlight"><code class="highlight">    <i><c- n><c- n>integral</c-></c-></i> <c- n><c- n>fetch_add</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- nf><c- nf>fetch_add</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- nf><c- nf>fetch_sub</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- nf><c- nf>fetch_sub</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- nf><c- nf>fetch_and</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- nf><c- nf>fetch_and</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- nf><c- nf>fetch_or</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- nf><c- nf>fetch_or</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- nf><c- nf>fetch_xor</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- nf><c- nf>fetch_xor</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->

    <c- n><c- n>atomic</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>default</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>constexpr</c-></c-> <c- nf><c- nf>atomic</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>atomic</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->

    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>++</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>int</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>++</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>int</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>--</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>int</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>--</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>int</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>++</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>++</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>--</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>--</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>+=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>+=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>-=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>-=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>&amp;=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>&amp;=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>|=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>|=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>^=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>integral</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>^=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>integral</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- p><c- p>};</c-></c->
<c- p><c- p>}</c-></c->
</code></pre>
   </blockquote>
   <p>Modify <a href="http://eel.is/c++draft/atomics.types.float#1">[<strong>atomics.types.float</strong>] paragraph 1</a> as follows:</p>
   <blockquote>
     <b>30.7.3 Specializations for floating-point types <span style="float: right;">[atomics.types.float]</span></b> 
    <div class="numbered"> There are specializations of the <code class="highlight"><c- n>atomic</c-></code> class template for the floating-point types <code class="highlight"><c- b>float</c-></code>, <code class="highlight"><c- b>double</c-></code>, and <code class="highlight"><c- b>long</c-> <c- b>double</c-></code>.
For each such type <code class="highlight"><i><c- n>floating</c-><c- o>-</c-><c- n>point</c-></i></code>, the specialization <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><i><c- n>floating</c-><c- o>-</c-><c- n>point</c-></i><c- o>></c-></code> provides additional atomic operations appropriate to floating-point types. </div>
<pre class="highlight"><code class="highlight"><c- k><c- k>namespace</c-></c-> <c- n><c- n>std</c-></c-> <c- p><c- p>{</c-></c->
  <c- k><c- k>template</c-></c-><c- o><c- o>&lt;></c-></c-> <c- k><c- k>struct</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&lt;</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- o><c- o>></c-></c-> <c- p><c- p>{</c-></c->
    <c- k><c- k>using</c-></c-> <c- n><c- n>value_type</c-></c-> <c- o><c- o>=</c-></c-> <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>;</c-></c->
    <c- k><c- k>using</c-></c-> <c- n><c- n>difference_type</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>value_type</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>static</c-></c-> <c- k><c- k>constexpr</c-></c-> <c- b><c- b>bool</c-></c-> <c- n><c- n>is_always_lock_free</c-></c-> <c- o><c- o>=</c-></c-> <i><c- n><c- n>implementation</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>defined</c-></c-></i><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>is_lock_free</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>is_lock_free</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>void</c-></c-> <c- nf><c- nf>store</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>void</c-></c-> <c- nf><c- nf>store</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i> <c- n><c- n>load</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i> <c- n><c- n>load</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>operator</c-></c-> <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>operator</c-></c-> <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i> <c- n><c- n>exchange</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>,</c-></c->
                             <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i> <c- n><c- n>exchange</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>,</c-></c->
                             <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_weak</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>,</c-></c->
                               <c- n><c- n>memory_order</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_weak</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>,</c-></c->
                               <c- n><c- n>memory_order</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_strong</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>,</c-></c->
                                 <c- n><c- n>memory_order</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_strong</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>,</c-></c->
                                 <c- n><c- n>memory_order</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_weak</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>,</c-></c->
                               <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_weak</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>,</c-></c->
                               <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_strong</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>,</c-></c->
                                 <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_strong</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>,</c-></c->
                                 <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
</code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>wait</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i> <c- n><c- n>old</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>wait</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i> <c- n><c- n>old</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_one</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_one</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_all</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_all</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="highlight"><code class="highlight"> 
    <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i> <c- n><c- n>fetch_add</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>,</c-></c->
                                    <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i> <c- n><c- n>fetch_add</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>,</c-></c->
                                    <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i> <c- n><c- n>fetch_sub</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>,</c-></c->
                                    <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i> <c- n><c- n>fetch_sub</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>,</c-></c->
                                    <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->

    <c- n><c- n>atomic</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>default</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>constexpr</c-></c-> <c- nf><c- nf>atomic</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>atomic</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->

    <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>+=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>+=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>-=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i> <c- k><c- k>operator</c-></c-><c- o><c- o>-=</c-></c-><c- p><c- p>(</c-></c-><i><c- n><c- n>floating</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>point</c-></c-></i><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- p><c- p>};</c-></c->
<c- p><c- p>}</c-></c->
</code></pre>
   </blockquote>
   <p>Modify <a href="http://eel.is/c++draft/atomics.types.pointer#1">[<strong>atomics.types.pointer</strong>] paragraph 1</a> as follows:</p>
   <blockquote>
     <b>30.7.4 Partial specialization for pointers <span style="float: right;">[atomics.types.pointer]</span></b> 
<pre class="highlight"><code class="highlight"><c- k><c- k>namespace</c-></c-> <c- n><c- n>std</c-></c-> <c- p><c- p>{</c-></c->
  <c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>class</c-></c-> <c- nc><c- nc>T</c-></c-><c- o><c- o>></c-></c-> <c- k><c- k>struct</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*></c-></c-> <c- p><c- p>{</c-></c->
    <c- k><c- k>using</c-></c-> <c- n><c- n>value_type</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>using</c-></c-> <c- n><c- n>difference_type</c-></c-> <c- o><c- o>=</c-></c-> <c- b><c- b>ptrdiff_t</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>static</c-></c-> <c- k><c- k>constexpr</c-></c-> <c- b><c- b>bool</c-></c-> <c- n><c- n>is_always_lock_free</c-></c-> <c- o><c- o>=</c-></c-> <i><c- n><c- n>implementation</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>defined</c-></c-></i><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>is_lock_free</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>is_lock_free</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>void</c-></c-> <c- nf><c- nf>store</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>void</c-></c-> <c- nf><c- nf>store</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- nf><c- nf>load</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- nf><c- nf>load</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>operator</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>operator</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- nf><c- nf>exchange</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- nf><c- nf>exchange</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_weak</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_weak</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_strong</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_weak</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c->
                               <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_weak</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c->
                               <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_strong</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c->
                                 <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>compare_exchange_strong</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c->
                                 <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
</code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>wait</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- n><c- n>old</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>wait</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- n><c- n>old</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_one</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_one</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_all</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_all</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="highlight"><code class="highlight">    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- n><c- n>fetch_add</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- nf><c- nf>fetch_add</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- nf><c- nf>fetch_sub</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- nf><c- nf>fetch_sub</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->

    <c- n><c- n>atomic</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>default</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>constexpr</c-></c-> <c- nf><c- nf>atomic</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>atomic</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->

    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>++</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>int</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>++</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>int</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>--</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>int</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>--</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>int</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>++</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>++</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>--</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>--</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>+=</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>+=</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>-=</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>-=</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- p><c- p>};</c-></c->
<c- p><c- p>}</c-></c->
</code></pre>
    <div class="numbered"> There is a partial specialization of the <code class="highlight"><c- n>atomic</c-></code> class template for pointers.
Specializations of this partial specialization are standard-layout structs.
They each have a trivial default constructor and a trivial destructor. </div>
   </blockquote>
   <p>Modify <a href="http://eel.is/c++draft/atomics.flag">[<strong>atomics.flag</strong>]</a> as follows:</p>
   <blockquote>
     <b>30.9 Flag type and operations <span style="float: right;">[atomics.flag]</span></b> 
<pre class="highlight"><c- k>namespace</c-> <c- n>std</c-> <c- p>{</c->
  <c- k>struct</c-> <c- n>atomic_flag</c-> <c- p>{</c->
</pre>
    <ins>
<pre class="highlight">    <c- b>bool</c-> <c- nf>test</c-><c- p>(</c-><c- n>memory_order</c-> <c- o>=</c-> <c- n>memory_order_seq_cst</c-><c- p>)</c-> <c- k>volatile</c-> <c- k>noexcept</c-><c- p>;</c->
    <c- b>bool</c-> <c- nf>test</c-><c- p>(</c-><c- n>memory_order</c-> <c- o>=</c-> <c- n>memory_order_seq_cst</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
    </ins>
<pre class="highlight"><code class="highlight">    <c- b><c- b>bool</c-></c-> <c- n><c- n>test_and_set</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order_seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>test_and_set</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order_seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>void</c-></c-> <c- nf><c- nf>clear</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order_seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>void</c-></c-> <c- nf><c- nf>clear</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order_seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
</code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>wait</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>bool</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>wait</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>bool</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>memory_order</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>seq_cst</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_one</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_one</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_all</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>volatile</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="ins highlight"><code class="highlight">    <c- b><c- b>void</c-></c-> <c- nf><c- nf>notify_all</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c-></code></pre>
<pre class="highlight"><code class="highlight"> 
    <c- n><c- n>atomic_flag</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>default</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>atomic_flag</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>volatile</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
  <c- p><c- p>};</c-></c->
 
</code></pre>
    <ins>
<pre class="highlight">  <c- b>bool</c-> <c- nf>atomic_flag_test</c-><c- p>(</c-><c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
  <c- b>bool</c-> <c- nf>atomic_flag_test</c-><c- p>(</c-><c- n>atomic_flag</c-><c- o>*</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
  <c- b>bool</c-> <c- nf>atomic_flag_test_explicit</c-><c- p>(</c-><c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-><c- p>,</c-> <c- n>memory_order</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
  <c- b>bool</c-> <c- nf>atomic_flag_test_explicit</c-><c- p>(</c-><c- n>atomic_flag</c-><c- o>*</c-><c- p>,</c-> <c- n>memory_order</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
    </ins>
<pre class="highlight"><code class="highlight">  <c- b><c- b>bool</c-></c-> <c- n><c- n>atomic_flag_test_and_set</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- b><c- b>bool</c-></c-> <c- nf><c- nf>atomic_flag_test_and_set</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- b><c- b>bool</c-></c-> <c- nf><c- nf>atomic_flag_test_and_set_explicit</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- b><c- b>bool</c-></c-> <c- nf><c- nf>atomic_flag_test_and_set_explicit</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_flag_clear</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_flag_clear</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_flag_clear_explicit</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
  <c- b><c- b>void</c-></c-> <c- nf><c- nf>atomic_flag_clear_explicit</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>atomic_flag</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
</code></pre>
    <ins>
<pre class="highlight">  <c- b>void</c-> <c- nf>atomic_flag_wait</c-><c- p>(</c-><c- k>const</c-> <c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-><c- p>,</c-> <c- b>bool</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
  <c- b>void</c-> <c- nf>atomic_flag_wait</c-><c- p>(</c-><c- k>const</c-> <c- n>atomic_flag</c-><c- o>*</c-><c- p>,</c-> <c- b>bool</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
  <c- b>void</c-> <c- nf>atomic_flag_wait_explicit</c-><c- p>(</c-><c- k>const</c-> <c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-><c- p>,</c-> <c- b>bool</c-><c- p>,</c-> <c- n>memory_order</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
  <c- b>void</c-> <c- nf>atomic_flag_wait_explicit</c-><c- p>(</c-><c- k>const</c-> <c- n>atomic_flag</c-><c- o>*</c-><c- p>,</c-> <c- b>bool</c-><c- p>,</c-> <c- n>memory_order</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
  <c- b>void</c-> <c- nf>atomic_flag_notify_one</c-><c- p>(</c-><c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
  <c- b>void</c-> <c- nf>atomic_flag_notify_one</c-><c- p>(</c-><c- n>atomic_flag</c-><c- o>*</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
  <c- b>void</c-> <c- nf>atomic_flag_notify_all</c-><c- p>(</c-><c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-><c- p>)</c-> <c- k>const</c-> <c- k>noexcept</c-><c- p>;</c->
  <c- b>void</c-> <c- nf>atomic_flag_notify_all</c-><c- p>(</c-><c- n>atomic_flag</c-><c- o>*</c-><c- p>)</c-> <c- k>const</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
    </ins>
<pre class="highlight"><code class="highlight"> 
  #<c- n><c- n>define</c-></c-> <c- n><c- n>ATOMIC_FLAG_INIT</c-></c-> <i><c- n><c- n>see</c-></c-> <c- n><c- n>below</c-></c-></i>
</code></pre>
<pre class="highlight"><c- p>}</c->
</pre>
    <div class="numbered"> The <code class="highlight"><c- n>atomic_flag</c-></code> type provides the classic test-and-set functionality. It has two states, set and clear. </div>
    <div class="numbered"> Operations on an object of type <code class="highlight"><c- n>atomic_flag</c-></code> shall be lock-free.
[ <em>Note:</em> Hence the operations should also be address-free. — <em>end note</em> ] </div>
    <div class="numbered"> The <code class="highlight"><c- n>atomic_flag</c-></code> type is a standard-layout struct. It has a trivial default
constructor and a trivial destructor. </div>
    <div class="numbered">
      The macro <code class="highlight"><c- n>ATOMIC_FLAG_INIT</c-></code> shall be defined in such a way that it can be used to initialize an object of type <code class="highlight"><c- n>atomic_flag</c-></code> to the clear state.
The macro can be used in the form: 
<pre class="highlight"><c- n>atomic_flag</c-> <c- n>guard</c-> <c- o>=</c-> <c- n>ATOMIC_FLAG_INIT</c-><c- p>;</c-></pre>
     <p>It is unspecified whether the macro can be used in other initialization contexts.
For a complete static-duration object, that initialization shall be static.
Unless initialized with <code class="highlight"><c- n>ATOMIC_FLAG_INIT</c-></code>, it is unspecified whether an <code class="highlight"><c- n>atomic_flag</c-></code> object has an initial state of set or clear.</p>
    </div>
    <div class="ins">
<pre class="highlight"><c- b>bool</c-> <c- nf>atomic_flag_test</c-><c- p>(</c-><c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>bool</c-> <c- nf>atomic_flag_test</c-><c- p>(</c-><c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>bool</c-> <c- nf>atomic_flag_test_explicit</c-><c- p>(</c-><c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>,</c-> <c- n>memory_order</c-> <c- n>order</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>bool</c-> <c- nf>atomic_flag_test_explicit</c-><c- p>(</c-><c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>,</c-> <c- n>memory_order</c-> <c- n>order</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>bool</c-> <c- n>atomic_flag</c-><c- o>::</c-><c- n>test</c-><c- p>(</c-><c- n>memory_order</c-> <c- n>order</c-> <c- o>=</c-> <c- n>memory_order_seq_cst</c-><c- p>)</c-> <c- k>volatile</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>bool</c-> <c- n>atomic_flag</c-><c- o>::</c-><c- n>test</c-><c- p>(</c-><c- n>memory_order</c-> <c- n>order</c-> <c- o>=</c-> <c- n>memory_order_seq_cst</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
     <div class="newnumbered"> <em>Requires:</em> The <code class="highlight"><c- n>order</c-></code> argument shall not be <code class="highlight"><c- n>memory_order_release</c-></code> nor <code class="highlight"><c- n>memory_order_acq_rel</c-></code>. </div>
     <div class="newnumbered"> <em>Effects:</em> Memory is affected according to the value of <code class="highlight"><c- n>order</c-></code>. </div>
     <div class="newnumbered"> <em>Returns:</em> Atomically returns the value pointed to by <code class="highlight"><c- n>object</c-></code> or <code class="highlight"><c- k>this</c-></code>. </div>
    </div>
<pre class="highlight"><c- b>bool</c-> <c- nf>atomic_flag_test_and_set</c-><c- p>(</c-><c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>bool</c-> <c- nf>atomic_flag_test_and_set</c-><c- p>(</c-><c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>bool</c-> <c- nf>atomic_flag_test_and_set_explicit</c-><c- p>(</c-><c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>,</c->
                                       <c- n>memory_order</c-> <c- n>order</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>bool</c-> <c- nf>atomic_flag_test_and_set_explicit</c-><c- p>(</c-><c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>,</c-> <c- n>memory_order</c-> <c- n>order</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>bool</c-> <c- n>atomic_flag</c-><c- o>::</c-><c- n>test_and_set</c-><c- p>(</c-><c- n>memory_order</c-> <c- n>order</c-> <c- o>=</c-> <c- n>memory_order_seq_cst</c-><c- p>)</c-> <c- k>volatile</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>bool</c-> <c- n>atomic_flag</c-><c- o>::</c-><c- n>test_and_set</c-><c- p>(</c-><c- n>memory_order</c-> <c- n>order</c-> <c- o>=</c-> <c- n>memory_order_seq_cst</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
    <div class="numbered"> <em>Effects:</em> Atomically sets the value pointed to by <code class="highlight"><c- n>object</c-></code> or by <code class="highlight"><c- k>this</c-></code> to <code class="highlight">true</code>.
Memory is affected according to the value of <code class="highlight"><c- n>order</c-></code>.
These operations are atomic read-modify-write operations (4.7). </div>
    <div class="numbered"> <em>Returns:</em> Atomically, the value of the object immediately before the effects. </div>
<pre class="highlight"><c- b>void</c-> <c- nf>atomic_flag_clear</c-><c- p>(</c-><c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- nf>atomic_flag_clear</c-><c- p>(</c-><c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- nf>atomic_flag_clear_explicit</c-><c- p>(</c-><c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>,</c->
                                <c- n>memory_order</c-> <c- n>order</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- nf>atomic_flag_clear_explicit</c-><c- p>(</c-><c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>,</c-> <c- n>memory_order</c-> <c- n>order</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- n>atomic_flag</c-><c- o>::</c-><c- n>clear</c-><c- p>(</c-><c- n>memory_order</c-> <c- n>order</c-> <c- o>=</c-> <c- n>memory_order_seq_cst</c-><c- p>)</c-> <c- k>volatile</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- n>atomic_flag</c-><c- o>::</c-><c- n>clear</c-><c- p>(</c-><c- n>memory_order</c-> <c- n>order</c-> <c- o>=</c-> <c- n>memory_order_seq_cst</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
    <p><em>Requires:</em> The <code class="highlight"><c- n>order</c-></code> argument shall not be <code class="highlight"><c- n>memory_order_consume</c-></code>, <code class="highlight"><c- n>memory_order_acquire</c-></code>, nor <code class="highlight"><c- n>memory_order_acq_rel</c-></code>.</p>
    <p><em>Effects:</em> Atomically sets the value pointed to by <code class="highlight"><c- n>object</c-></code> or by <code class="highlight"><c- k>this</c-></code> to <code class="highlight">false</code>. Memory is affected according to the value of <code class="highlight"><c- n>order</c-></code>.</p>
    <div class="ins">
<pre class="highlight"><c- b>void</c-> <c- nf>atomic_flag_wait</c-><c- p>(</c-><c- k>const</c-> <c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>,</c-> <c- b>bool</c-> <c- n>old</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- nf>atomic_flag_wait</c-><c- p>(</c-><c- k>const</c-> <c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>,</c-> <c- b>bool</c-> <c- n>old</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- nf>atomic_flag_wait_explicit</c-><c- p>(</c-><c- k>const</c-> <c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>,</c->
                               <c- b>bool</c-> <c- n>old</c-><c- p>,</c-> <c- n>memory_order</c-> <c- n>order</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- nf>atomic_flag_wait_explicit</c-><c- p>(</c-><c- k>const</c-> <c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>,</c->
                               <c- b>bool</c-> <c- n>old</c-><c- p>,</c-> <c- n>memory_order</c-> <c- n>order</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- n>atomic_flag</c-><c- o>::</c-><c- n>wait</c-><c- p>(</c-><c- b>bool</c-> <c- n>old</c-><c- p>,</c->
                       <c- n>memory_order</c-> <c- n>order</c-> <c- o>=</c-> <c- n>memory_order</c-><c- o>::</c-><c- n>seq_cst</c-><c- p>)</c-> <c- k>const</c-> <c- k>volatile</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- n>atomic_flag</c-><c- o>::</c-><c- n>wait</c-><c- p>(</c-><c- b>bool</c-> <c- n>old</c-><c- p>,</c->
                       <c- n>memory_order</c-> <c- n>order</c-> <c- o>=</c-> <c- n>memory_order</c-><c- o>::</c-><c- n>seq_cst</c-><c- p>)</c-> <c- k>const</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
     <div class="numbered"> <em>Requires:</em> The <code class="highlight"><c- n>order</c-></code> argument shall not be <code class="highlight"><c- n>memory_order_release</c-></code> nor <code class="highlight"><c- n>memory_order_acq_rel</c-></code>. </div>
     <div class="numbered">
       <em>Effects:</em> Repeatedly performs the following steps, in order: 
      <ul>
       <li data-md>
        <p>Evaluates <code class="highlight"><c- n>object</c-><c- o>-></c-><c- n>load</c-><c- p>(</c-><c- n>order</c-><c- p>)</c-> <c- o>!=</c-> <c- n>old</c-></code> then, if the result is <code class="highlight">true</code>, returns.</p>
       <li data-md>
        <p>Blocks until an implementation-defined condition has been met.
[ <em>Note:</em> Consequently, it may unblock for reasons other than an <a data-link-type="dfn" href="#atomic-notifying-operations" id="ref-for-atomic-notifying-operations④">atomic notifying operation</a>. — <em>end note</em> ]</p>
      </ul>
     </div>
     <div class="numbered"> <em>Remarks:</em> This function is an <a data-link-type="dfn" href="#atomic-waiting-operations" id="ref-for-atomic-waiting-operations④">atomic waiting operation</a>. </div>
<pre class="highlight"><c- b>void</c-> <c- nf>atomic_flag_notify_one</c-><c- p>(</c-><c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- nf>atomic_flag_notify_one</c-><c- p>(</c-><c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>)</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- n>atomic_flag</c-><c- o>::</c-><c- n>notify_one</c-><c- p>()</c-> <c- k>volatile</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- n>atomic_flag</c-><c- o>::</c-><c- n>notify_one</c-><c- p>()</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
     <div class="numbered"> <em>Effects:</em> Unblocks up to one execution of a <a data-link-type="dfn" href="#atomic-waiting-operations" id="ref-for-atomic-waiting-operations⑤">atomic waiting operation</a> that blocked after observing the result of an atomic operation <code class="highlight"><c- n>X</c-></code>, if there exists another atomic operation <code class="highlight"><c- n>Y</c-></code>, such that <code class="highlight"><c- n>X</c-></code> precedes <code class="highlight"><c- n>Y</c-></code> in the modification order of <code class="highlight"><c- o>*</c-><c- n>object</c-></code> or <code class="highlight"><c- o>*</c-><c- k>this</c-></code>, and <code class="highlight"><c- n>Y</c-></code> happens before this call. </div>
     <div class="numbered"> <em>Remarks:</em> This function is an <a data-link-type="dfn" href="#atomic-notifying-operations" id="ref-for-atomic-notifying-operations⑤">atomic notifying operation</a>. </div>
<pre class="highlight"><c- b>void</c-> <c- nf>atomic_flag_notify_all</c-><c- p>(</c-><c- k>volatile</c-> <c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>)</c-> <c- k>const</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- nf>atomic_flag_notify_all</c-><c- p>(</c-><c- n>atomic_flag</c-><c- o>*</c-> <c- n>object</c-><c- p>)</c-> <c- k>const</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- n>atomic_flag</c-><c- o>::</c-><c- n>notify_all</c-><c- p>()</c-> <c- k>volatile</c-> <c- k>noexcept</c-><c- p>;</c->
<c- b>void</c-> <c- n>atomic_flag</c-><c- o>::</c-><c- n>notify_all</c-><c- p>()</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
     <div class="numbered"> <em>Effects:</em> Unblocks each execution of a <a data-link-type="dfn" href="#atomic-waiting-operations" id="ref-for-atomic-waiting-operations⑥">atomic waiting operation</a> that blocked after observing the result of an atomic operation <code class="highlight"><c- n>X</c-></code>, if there exists another atomic operation <code class="highlight"><c- n>Y</c-></code>, such that <code class="highlight"><c- n>X</c-></code> precedes <code class="highlight"><c- n>Y</c-></code> in the modification order of <code class="highlight"><c- o>*</c-><c- n>object</c-></code> or <code class="highlight"><c- o>*</c-><c- k>this</c-></code>, and <code class="highlight"><c- n>Y</c-></code> happens before this call. </div>
     <div class="numbered"> <em>Remarks:</em> This function is an <a data-link-type="dfn" href="#atomic-notifying-operations" id="ref-for-atomic-notifying-operations⑥">atomic notifying operation</a>. </div>
    </div>
   </blockquote>
   <p>Modify Table 134 "Thread support library summary" in <a href="http://eel.is/c++draft/thread.general">[<strong>thread.general</strong>]</a> as follows:</p>
   <blockquote>
    <div style="text-align: center;"> Table 134 — Thread support library summary </div>
    <table border="1" style="margin: auto;">
     <tbody>
      <tr>
       <th>
       <th>Subclause
       <th>Header(s)
      <tr>
       <td>31.2
       <td>Requirements
       <td>
      <tr>
       <td>31.3
       <td>Threads
       <td><code class="highlight"><c- o>&lt;</c-><c- n>thread</c-><c- o>></c-></code>
      <tr>
       <td>31.4
       <td>Mutual exclusion
       <td><code class="highlight"><c- o>&lt;</c-><c- n>mutex</c-><c- o>></c-></code> <code class="highlight"><c- o>&lt;</c-><c- n>shared_mutex</c-><c- o>></c-></code>
      <tr>
       <td>31.5
       <td>Condition variables
       <td><code class="highlight"><c- o>&lt;</c-><c- n>condition_variable</c-><c- o>></c-></code>
      <tr class="ins">
       <td>31.�
       <td>Semaphores
       <td><code class="highlight"><c- o>&lt;</c-><c- n>semaphore</c-><c- o>></c-></code>
      <tr class="ins">
       <td>31.�
       <td>Latches and barriers
       <td><code class="highlight"><c- o>&lt;</c-><c- n>latch</c-><c- o>></c-></code> <code class="highlight"><c- o>&lt;</c-><c- n>barrier</c-><c- o>></c-></code>
      <tr>
       <td>31.6
       <td>Futures
       <td><code class="highlight"><c- o>&lt;</c-><c- n>future</c-><c- o>></c-></code>
    </table>
   </blockquote>
   <p>Add two new subclauses after <a href="http://eel.is/c++draft/thread.condition">[<strong>thread.condition</strong>]</a>:</p>
   <blockquote class="ins">
     <b>31.� Semaphores <span style="float: right;">[thread.semaphore]</span></b> 
    <div class="numbered"> Semaphores are lightweight synchronization primitives used to constrain concurrent access to a shared resource. They are widely used to implement other synchronization primitives and, whenever both are applicable, can be more efficient than condition variables. </div>
    <div class="numbered"> A counting semaphore is a semaphore object that models a non-negative resource count. A binary semaphore is a semaphore object that has only two states, also known as available and unavailable.
[ <em>Note:</em> A binary semaphore should be more efficient than a counting semaphore with a unit magnitude count. – <em>end note</em> ] </div>
   </blockquote>
   <blockquote class="ins">
     <b>31.�.1 Header <code class="highlight"><c- o>&lt;</c-><c- n>semaphore</c-><c- o>></c-></code> synopsis <span style="float: right;">[thread.semaphore.syn]</span></b> 
<pre class="highlight"><code class="highlight"><c- k><c- k>namespace</c-></c-> <c- n><c- n>std</c-></c-> <c- p><c- p>{</c-></c->  
  <c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- b><c- b>ptrdiff_t</c-></c-> <c- n><c- n>least_max_value</c-></c-> <c- o><c- o>=</c-></c-> <i><c- n><c- n>implementation</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>defined</c-></c-></i><c- o><c- o>></c-></c->
    <c- k><c- k>class</c-></c-> <c- nc><c- nc>counting_semaphore</c-></c-><c- p><c- p>;</c-></c->

  <c- k><c- k>using</c-></c-> <c- n><c- n>binary_semaphore</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>counting_semaphore</c-></c-><c- o><c- o>&lt;</c-></c-><c- mi><c- mi>1</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c->
<c- p><c- p>}</c-></c->
</code></pre>
   </blockquote>
   <blockquote class="ins">
     <b>31.�.2 Class template <code class="highlight"><c- n>counting_semaphore</c-></code> <span style="float: right;">[thread.semaphore.counting.class]</span></b> 
<pre class="highlight"><code class="highlight"><c- k><c- k>namespace</c-></c-> <c- n><c- n>std</c-></c-> <c- p><c- p>{</c-></c->
  <c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- b><c- b>ptrdiff_t</c-></c-> <c- n><c- n>least_max_value</c-></c-><c- o><c- o>></c-></c->
  <c- k><c- k>class</c-></c-> <c- nc><c- nc>counting_semaphore</c-></c-> <c- p><c- p>{</c-></c->
  <c- k><c- k>public</c-></c-><c- o><c- o>:</c-></c->
    <c- k><c- k>static</c-></c-> <c- k><c- k>constexpr</c-></c-> <c- b><c- b>ptrdiff_t</c-></c-> <c- n><c- n>max</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->

    <c- k><c- k>constexpr</c-></c-> <c- k><c- k>explicit</c-></c-> <c- nf><c- nf>counting_semaphore</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-> <c- n><c- n>desired</c-></c-><c- p><c- p>);</c-></c->
    <c- o><c- o>~</c-></c-><c- n><c- n>counting_semaphore</c-></c-><c- p><c- p>();</c-></c->

    <c- n><c- n>counting_semaphore</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>basic_semaphore</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>counting_semaphore</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>basic_semaphore</c-></c-><c- o><c- o>&amp;&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>counting_semaphore</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>basic_semaphore</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>counting_semaphore</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>basic_semaphore</c-></c-><c- o><c- o>&amp;&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->

    <c- b><c- b>void</c-></c-> <c- nf><c- nf>release</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-> <c- n><c- n>update</c-></c-> <c- o><c- o>=</c-></c-> <c- mi><c- mi>1</c-></c-><c- p><c- p>);</c-></c->
    <c- b><c- b>void</c-></c-> <c- nf><c- nf>acquire</c-></c-><c- p><c- p>();</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>try_acquire</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>class</c-></c-> <c- nc><c- nc>Rep</c-></c-><c- p><c- p>,</c-></c-> <c- k><c- k>class</c-></c-> <c- nc><c- nc>Period</c-></c-><c- o><c- o>></c-></c->
      <c- b><c- b>bool</c-></c-> <c- n><c- n>try_acquire_for</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>chrono</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>duration</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>Rep</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>Period</c-></c-><c- o><c- o>>&amp;</c-></c-> <c- n><c- n>rel_time</c-></c-><c- p><c- p>);</c-></c->
    <c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>class</c-></c-> <c- nc><c- nc>Clock</c-></c-><c- p><c- p>,</c-></c-> <c- k><c- k>class</c-></c-> <c- nc><c- nc>Duration</c-></c-><c- o><c- o>></c-></c->
      <c- b><c- b>bool</c-></c-> <c- n><c- n>try_acquire_until</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>chrono</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>time_point</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>Clock</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>Duration</c-></c-><c- o><c- o>>&amp;</c-></c-> <c- n><c- n>abs_time</c-></c-><c- p><c- p>);</c-></c->

  <c- k><c- k>private</c-></c-><c- o><c- o>:</c-></c->
    <c- b><c- b>ptrdiff_t</c-></c-> <c- n><c- n>counter</c-></c-><c- p><c- p>;</c-></c-> <i><c- c1><c- c1>// exposition only</c-></c-></i>
  <c- p><c- p>};</c-></c->
<c- p><c- p>}</c-></c->
</code></pre>
    <div class="numbered"> Class <code class="highlight"><c- n>counting_semaphore</c-></code> maintains an internal counter that is initialized when the semaphore is created. Threads may block waiting until <code class="highlight"><c- n>counter</c-> <c- o>>=</c-> <c- mi>1</c-></code>. </div>
    <div class="numbered"> Semaphores permit concurrent invocation of the <code class="highlight"><c- n>release</c-></code>, <code class="highlight"><c- n>acquire</c-></code>, <code class="highlight"><c- n>try_acquire</c-></code>, <code class="highlight"><c- n>try_acquire_for</c-></code>, and <code class="highlight"><c- n>try_acquire_until</c-></code> member functions. </div>
<pre class="highlight"><c- k>static</c-> <c- k>constexpr</c-> <c- b>ptrdiff_t</c-> <c- nf>max</c-><c- p>()</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
    <div class="numbered"> <em>Returns:</em> The maximum value of <code class="highlight"><c- n>counter</c-></code>. This value shall not be less than that of the template argument <code class="highlight"><c- n>least_max_value</c-></code>.
[ <em>Note:</em> The value may exceed least_max_value. – <em>end note</em> ] </div>
<pre class="highlight"><c- k>constexpr</c-> <c- k>explicit</c-> <c- nf>counting_semaphore</c-><c- p>(</c-><c- b>ptrdiff_t</c-> <c- n>desired</c-><c- p>);</c->
</pre>
    <div class="numbered"> <em>Requires:</em> <code class="highlight"><c- n>desired</c-> <c- o>>=</c-> <c- mi>0</c-></code> and <code class="highlight"><c- n>desired</c-> <c- o>&lt;=</c-> <c- n>max</c-><c- p>()</c-></code>. </div>
    <div class="numbered"> <em>Effects:</em> <code class="highlight"><c- n>counter</c-> <c- o>=</c-> <c- n>desired</c-></code>. </div>
    <div class="numbered"> <em>Throws:</em> Nothing. </div>
<pre class="highlight"><c- o>~</c-><c- n>counting_semaphore</c-><c- p>();</c->
</pre>
    <div class="numbered"> <em>Requires:</em> For every function call that blocks on <code class="highlight"><c- n>counter</c-></code>, a function call that will cause it to unblock and return shall happen before this call.
[ <em>Note:</em> This relaxes the usual rules, which would have required all wait calls to happen before destruction. — <em>end note</em> ] </div>
    <div class="numbered"> <em>Effects:</em> Destroys the object. </div>
    <div class="numbered"> <em>Throws:</em> Nothing. </div>
<pre class="highlight"><c- b>void</c-> <c- nf>release</c-><c- p>(</c-><c- b>ptrdiff_t</c-> <c- n>update</c-> <c- o>=</c-> <c- mi>1</c-><c- p>);</c->
</pre>
    <div class="numbered"> <em>Requires:</em> <code class="highlight"><c- n>update</c-> <c- o>>=</c-> <c- mi>0</c-></code>, and <code class="highlight"><c- n>counter</c-> <c- o>+</c-> <c- n>update</c-> <c- o>&lt;=</c-> <c- n>max</c-><c- p>()</c-></code>. </div>
    <div class="numbered"> <em>Effects:</em> <code class="highlight"><c- n>counter</c-> <c- o>+=</c-> <c- n>update</c-></code>, executed atomically. If any threads are blocked on counter, unblocks them. </div>
    <div class="numbered"> <em>Synchronization:</em> Strongly happens before invocations of <code class="highlight"><c- n>try_acquire</c-></code> that observe the result of the effects. </div>
    <div class="numbered"> <em>Throws:</em> <code class="highlight"><c- n>system_error</c-></code> when an exception is required (<a href="http://eel.is/c++draft/thread.req.exception">31.2.2</a>). </div>
<pre class="highlight"><c- b>bool</c-> <c- nf>try_acquire</c-><c- p>()</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
    <div class="numbered">
      <em>Effects:</em> 
     <ul>
      <li data-md>
       <p>With low probability, returns immediately. [ <em>Note:</em> An implementation should ensure that <code class="highlight"><c- n>try_acquire</c-></code> does not consistently return <code class="highlight">false</code> in the absence of contending acquisitions. — <em>end note</em> ]</p>
      <li data-md>
       <p>Otherwise, if <code class="highlight"><c- n>counter</c-> <c- o>>=</c-> <c- mi>1</c-></code>, then <code class="highlight"><c- n>counter</c-> <c- o>-=</c-> <c- mi>1</c-></code> is executed atomically.</p>
     </ul>
    </div>
    <div class="numbered"> <em>Returns:</em> <code class="highlight">true</code> if <code class="highlight"><c- n>counter</c-></code> was decremented, otherwise <code class="highlight">false</code>. </div>
<pre class="highlight"><c- b>void</c-> <c- nf>acquire</c-><c- p>();</c->
</pre>
    <div class="numbered">
      <em>Effects:</em> Repeatedly performs the following steps, in order: 
     <ul>
      <li data-md>
       <p>Evaluates <code class="highlight"><c- n>try_acquire</c-></code>, then, if the result is <code class="highlight">true</code>, returns.</p>
      <li data-md>
       <p>Blocks until <code class="highlight"><c- n>counter</c-> <c- o>>=</c-> <c- mi>1</c-></code>.</p>
     </ul>
    </div>
    <div class="numbered"> <em>Throws:</em> <code class="highlight"><c- n>system_error</c-></code> when an exception is required (<a href="http://eel.is/c++draft/thread.req.exception">31.2.2</a>). </div>
<pre class="highlight"><c- k>template</c-><c- o>&lt;</c-><c- k>class</c-> <c- nc>Rep</c-><c- p>,</c-> <c- k>class</c-> <c- nc>Period</c-><c- o>></c->
  <c- b>bool</c-> <c- n>try_acquire_for</c-><c- p>(</c-><c- k>const</c-> <c- n>chrono</c-><c- o>::</c-><c- n>duration</c-><c- o>&lt;</c-><c- n>Rep</c-><c- p>,</c-> <c- n>Period</c-><c- o>>&amp;</c-> <c- n>rel_time</c-><c- p>);</c->
<c- k>template</c-><c- o>&lt;</c-><c- k>class</c-> <c- nc>Clock</c-><c- p>,</c-> <c- k>class</c-> <c- nc>Duration</c-><c- o>></c->
  <c- b>bool</c-> <c- n>try_acquire_until</c-><c- p>(</c-><c- k>const</c-> <c- n>chrono</c-><c- o>::</c-><c- n>time_point</c-><c- o>&lt;</c-><c- n>Clock</c-><c- p>,</c-> <c- n>Duration</c-><c- o>>&amp;</c-> <c- n>abs_time</c-><c- p>);</c->
</pre>
    <div class="numbered">
      <em>Effects:</em> Repeatedly performs the following steps, in order: 
     <ul>
      <li data-md>
       <p>Evaluates <code class="highlight"><c- n>try_acquire</c-></code>. If the result is <code class="highlight">true</code>, returns <code class="highlight">true</code>.</p>
      <li data-md>
       <p>Blocks until the timeout expires or <code class="highlight"><c- n>counter</c-> <c- o>>=</c-> <c- mi>1</c-></code>. If the timeout expired, returns <code class="highlight">false</code>.</p>
     </ul>
    </div>
    <div class="numbered"> <em>Throws:</em> Timeout-related exceptions (<a href="http://eel.is/c++draft/thread.req.timing">31.2.4</a>). </div>
   </blockquote>
   <blockquote class="ins">
     <b>31.� Coordination Types <span style="float: right;">[thread.coord]</span></b> 
    <div class="numbered"> This section describes various concepts related to thread coordination, and defines the <dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="coordination-types">coordination types</dfn> <code class="highlight"><c- n>latch</c-></code> and <code class="highlight"><c- n>barrier</c-></code>. These types facilitate concurrent computation performed by a number of threads, in one or more <dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="phases">phases</dfn>. </div>
    <div class="numbered"> In this subclause, a synchronization point represents a condition that a thread may contribute to or wait for, potentially blocking until it is satisfied. A thread arrives at the synchronization point when it has an effect on the state of the condition, even if it does not cause it to become satisfied. </div>
    <div class="numbered"> Concurrent invocations of the member functions of <a data-link-type="dfn" href="#coordination-types" id="ref-for-coordination-types">coordination types</a>, other than their destructors, do not introduce data races. </div>
   </blockquote>
   <blockquote class="ins">
     <b>31.�.1 Latches <span style="float: right;">[thread.coord.latch]</span></b> 
    <div class="numbered"> A latch is a thread coordination mechanism that allows any number of threads to block until an expected count is summed (exactly) by threads that arrived at the latch. The expected count is set when the latch is constructed. An individual latch is a single-use object; once the count has been reached, the latch cannot be reused. </div>
   </blockquote>
   <blockquote class="ins">
     <b>31.�.1.1 Header <code class="highlight"><c- o>&lt;</c-><c- n>latch</c-><c- o>></c-></code> synopsis <span style="float: right;">[thread.coord.latch.syn]</span></b> 
<pre class="highlight"><c- k>namespace</c-> <c- n>std</c-> <c- p>{</c->
  <c- k>class</c-> <c- nc>latch</c-><c- p>;</c->
<c- p>}</c->
</pre>
   </blockquote>
   <blockquote class="ins">
     <b>31.�.1.2 Class <code class="highlight"><c- n>latch</c-></code> <span style="float: right;">[thread.coord.latch.class]</span></b> 
<pre class="highlight"><code class="highlight"><c- k><c- k>namespace</c-></c-> <c- n><c- n>std</c-></c-> <c- p><c- p>{</c-></c->
  <c- k><c- k>class</c-></c-> <c- nc><c- nc>latch</c-></c-> <c- p><c- p>{</c-></c->
  <c- k><c- k>public</c-></c-><c- o><c- o>:</c-></c->
    <c- k><c- k>constexpr</c-></c-> <c- k><c- k>explicit</c-></c-> <c- n><c- n>latch</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-> <c- n><c- n>expected</c-></c-><c- p><c- p>);</c-></c->
    <c- o><c- o>~</c-></c-><c- n><c- n>latch</c-></c-><c- p><c- p>();</c-></c->

    <c- n><c- n>latch</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>latch</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>latch</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>latch</c-></c-><c- o><c- o>&amp;&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>latch</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>latch</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>latch</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>latch</c-></c-><c- o><c- o>&amp;&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    
    <c- b><c- b>void</c-></c-> <c- nf><c- nf>count_down</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-> <c- n><c- n>update</c-></c-> <c- o><c- o>=</c-></c-> <c- mi><c- mi>1</c-></c-><c- p><c- p>);</c-></c->
    <c- b><c- b>bool</c-></c-> <c- nf><c- nf>try_wait</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>void</c-></c-> <c- nf><c- nf>wait</c-></c-><c- p><c- p>()</c-></c-> <c- k><c- k>const</c-></c-><c- p><c- p>;</c-></c->
    <c- b><c- b>void</c-></c-> <c- nf><c- nf>arrive_and_wait</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-> <c- n><c- n>update</c-></c-> <c- o><c- o>=</c-></c-> <c- mi><c- mi>1</c-></c-><c- p><c- p>);</c-></c->

  <c- k><c- k>private</c-></c-><c- o><c- o>:</c-></c->
    <c- b><c- b>ptrdiff_t</c-></c-> <c- n><c- n>counter</c-></c-><c- p><c- p>;</c-></c-> <i><c- c1><c- c1>// exposition only</c-></c-></i>
  <c- p><c- p>};</c-></c->
<c- p><c- p>}</c-></c-> 
</code></pre>
    <div class="numbered"> A <code class="highlight"><c- n>latch</c-></code> maintains an internal counter that is initialized when the <code class="highlight"><c- n>latch</c-></code> is created. Threads may block at the <code class="highlight"><c- n>latch</c-></code>’s synchronization point, waiting for <code class="highlight"><c- n>counter</c-></code> to be decremented to <code class="highlight"><c- mi>0</c-></code>. </div>
<pre class="highlight"><c- k>constexpr</c-> <c- k>explicit</c-> <c- nf>latch</c-><c- p>(</c-><c- b>ptrdiff_t</c-> <c- n>expected</c-><c- p>);</c->
</pre>
    <div class="numbered"> <em>Requires:</em> <code class="highlight"><c- n>expected</c-> <c- o>>=</c-> <c- mi>0</c-></code>. </div>
    <div class="numbered"> <em>Effects:</em> <code class="highlight"><c- n>counter</c-> <c- o>=</c-> <c- n>expected</c-></code>. </div>
    <div class="numbered"> <em>Throws:</em> Nothing. </div>
<pre class="highlight"><c- o>~</c-><c- n>latch</c-><c- p>();</c->
</pre>
    <div class="numbered"> <em>Requires:</em> No threads are blocked at the synchronization point. </div>
    <div class="numbered"> <em>Effects:</em> Destroys the latch. </div>
    <div class="numbered"> <em>Throws:</em> Nothing. </div>
    <div class="numbered"> <em>Remarks:</em> May be called even if some threads have not yet returned from functions that block at the synchronization point, provided that they are unblocked. [ <em>Note:</em> The destructor may block until all threads have exited invocations of <code class="highlight"><c- n>wait</c-></code> on this object. — <em>end note</em> ] </div>
<pre class="highlight"><c- b>void</c-> <c- nf>count_down</c-><c- p>(</c-><c- b>ptrdiff_t</c-> <c- n>update</c-> <c- o>=</c-> <c- mi>1</c-><c- p>);</c->
</pre>
    <div class="numbered"> <em>Requires:</em> <code class="highlight"><c- n>counter</c-> <c- o>>=</c-> <c- n>update</c-></code> and <code class="highlight"><c- n>update</c-> <c- o>>=</c-> <c- mi>0</c-></code>. </div>
    <div class="numbered"> <em>Effects:</em> Atomically decrements <code class="highlight"><c- n>counter</c-></code> by <code class="highlight"><c- n>update</c-></code>. </div>
    <div class="numbered"> <em>Synchronization:</em> Synchronizes with the returns from all calls unblocked by the effects. </div>
    <div class="numbered"> <em>Throws:</em> <code class="highlight"><c- n>system_error</c-></code> when an exception is required (<a href="http://eel.is/c++draft/thread.req.exception">31.2.2</a>). </div>
    <div class="numbered"> <em>Remarks:</em> Arrives at the synchronization point with <code class="highlight"><c- n>update</c-></code> count. </div>
<pre class="highlight"><c- b>bool</c-> <c- nf>try_wait</c-><c- p>()</c-> <c- k>const</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
    <div class="numbered"> <em>Returns:</em> <code class="highlight"><c- n>counter</c-> <c- o>==</c-> <c- mi>0</c-></code>. </div>
<pre class="highlight"><c- b>void</c-> <c- nf>wait</c-><c- p>()</c-> <c- k>const</c-> <c- k>noexcept</c-><c- p>;</c->
</pre>
    <div class="numbered"> <em>Effects:</em> If <code class="highlight"><c- n>counter</c-> <c- o>==</c-> <c- mi>0</c-></code>, returns immediately. Otherwise, blocks the calling thread at the synchronization point until <code class="highlight"><c- n>counter</c-> <c- o>==</c-> <c- mi>0</c-></code>. </div>
    <div class="numbered"> <em>Throws:</em> <code class="highlight"><c- n>system_error</c-></code> when an exception is required (<a href="http://eel.is/c++draft/thread.req.exception">31.2.2</a>). </div>
<pre class="highlight"><c- b>void</c-> <c- nf>arrive_and_wait</c-><c- p>(</c-><c- b>ptrdiff_t</c-> <c- n>update</c-> <c- o>=</c-> <c- mi>1</c-><c- p>);</c->
</pre>
    <div class="numbered"> <em>Effects:</em> Equivalent to <code class="highlight"><c- n>count_down</c-><c- p>(</c-><c- n>update</c-><c- p>);</c-> <c- n>wait</c-><c- p>();</c-></code>. </div>
    <div class="numbered"> <em>Throws:</em> <code class="highlight"><c- n>system_error</c-></code> when an exception is required (<a href="http://eel.is/c++draft/thread.req.exception">31.2.2</a>). </div>
   </blockquote>
   <blockquote class="ins">
     <b>31.�.2 Barriers <span style="float: right;">[thread.coord.barrier]</span></b> 
    <div class="numbered"> A barrier is a thread coordination mechanism that allows at most an expected count of threads to block until that count is summed (exactly) by threads that arrived at the barrier in each of its successive <a data-link-type="dfn" href="#phases" id="ref-for-phases">phases</a>. Once threads are released from blocking at the synchronization point for a <a data-link-type="dfn" href="#phases" id="ref-for-phases①">phase</a>, they can reuse the same barrier immediately in its next <a data-link-type="dfn" href="#phases" id="ref-for-phases②">phase</a>. [ <em>Note:</em> It is thus useful for managing repeated tasks, or <a data-link-type="dfn" href="#phases" id="ref-for-phases③">phases</a> of a larger task, that are handled by multiple threads. — <em>end note</em> ] </div>
    <div class="numbered">
      A barrier has a <dfn class="dfn-paneled" data-dfn-type="dfn" data-noexport id="completion-step">completion step</dfn> that is a (possibly empty) set of effects associated with a <a data-link-type="dfn" href="#phases" id="ref-for-phases④">phase</a> of the barrier. When the member functions defined in this subclause arrive at the barrier, they have the following effects: 
     <ul>
      <li data-md>
       <p>When the expected number of threads for this <a data-link-type="dfn" href="#phases" id="ref-for-phases⑤">phase</a> have arrived at the barrier, one of those threads executes the barrier type’s <a data-link-type="dfn" href="#completion-step" id="ref-for-completion-step">completion step</a>.</p>
      <li data-md>
       <p>When the <a data-link-type="dfn" href="#completion-step" id="ref-for-completion-step①">completion step</a> is completed, all threads blocked at the synchronization point for this <a data-link-type="dfn" href="#phases" id="ref-for-phases⑥">phase</a> are unblocked and the barrier enters its next <a data-link-type="dfn" href="#phases" id="ref-for-phases⑦">phase</a>. The end of the <a data-link-type="dfn" href="#completion-step" id="ref-for-completion-step②">completion step</a> strongly happens before the returns from all calls unblocked by its completion.</p>
     </ul>
    </div>
   </blockquote>
   <blockquote class="ins">
     <b>31.�.2.1 Header <code class="highlight"><c- o>&lt;</c-><c- n>barrier</c-><c- o>></c-></code> synopsis <span style="float: right;">[thread.coord.barrier.syn]</span></b> 
<pre class="highlight"><code class="highlight"><c- k><c- k>namespace</c-></c-> <c- n><c- n>std</c-></c-> <c- p><c- p>{</c-></c->
  <c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>class</c-></c-> <c- nc><c- nc>CompletionFunction</c-></c-> <c- o><c- o>=</c-></c-> <i><c- n><c- n>implementation</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>defined</c-></c-></i><c- o><c- o>></c-></c->
    <c- k><c- k>class</c-></c-> <c- nc><c- nc>barrier</c-></c-><c- p><c- p>;</c-></c->
<c- p><c- p>}</c-></c->
</code></pre>
   </blockquote>
   <blockquote class="ins">
     <b>31.�.2.2 Class template <code class="highlight"><c- n>barrier</c-></code> <span style="float: right;">[thread.coord.barrier.class]</span></b> 
<pre class="highlight"><code class="highlight"><c- k><c- k>namespace</c-></c-> <c- n><c- n>std</c-></c-> <c- p><c- p>{</c-></c->
  <c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>class</c-></c-> <c- nc><c- nc>CompletionFunction</c-></c-><c- o><c- o>></c-></c->
  <c- k><c- k>class</c-></c-> <c- nc><c- nc>barrier</c-></c-> <c- p><c- p>{</c-></c->
  <c- k><c- k>public</c-></c-><c- o><c- o>:</c-></c->
    <c- k><c- k>using</c-></c-> <c- n><c- n>arrival_token</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>implementation</c-></c-><c- o><c- o>-</c-></c-><c- n><c- n>defined</c-></c-><c- p><c- p>;</c-></c->

    <c- k><c- k>constexpr</c-></c-> <c- k><c- k>explicit</c-></c-> <c- nf><c- nf>barrier</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-> <c- n><c- n>expected</c-></c-><c- p><c- p>,</c-></c->
                               <c- n><c- n>CompletionFunction</c-></c-> <c- n><c- n>f</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>CompletionFunction</c-></c-><c- p><c- p>());</c-></c->

    <c- o><c- o>~</c-></c-><c- n><c- n>barrier</c-></c-><c- p><c- p>();</c-></c->

    <c- n><c- n>barrier</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>barrier</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>barrier</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>barrier</c-></c-><c- o><c- o>&amp;&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>barrier</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>barrier</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->
    <c- n><c- n>barrier</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>barrier</c-></c-><c- o><c- o>&amp;&amp;</c-></c-><c- p><c- p>)</c-></c-> <c- o><c- o>=</c-></c-> <c- k><c- k>delete</c-></c-><c- p><c- p>;</c-></c->

    <c- p><c- p>[[</c-></c-><c- n><c- n>nodiscard</c-></c-><c- p><c- p>]]</c-></c-> <c- n><c- n>arrival_token</c-></c-> <c- n><c- n>arrive</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-> <c- n><c- n>update</c-></c-> <c- o><c- o>=</c-></c-> <c- mi><c- mi>1</c-></c-><c- p><c- p>);</c-></c->
    <c- b><c- b>void</c-></c-> <c- nf><c- nf>wait</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>arrival_token</c-></c-><c- o><c- o>&amp;&amp;</c-></c-> <c- n><c- n>arrival</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>const</c-></c-><c- p><c- p>;</c-></c->

    <c- b><c- b>void</c-></c-> <c- nf><c- nf>arrive_and_wait</c-></c-><c- p><c- p>();</c-></c->
    <c- b><c- b>void</c-></c-> <c- nf><c- nf>arrive_and_drop</c-></c-><c- p><c- p>();</c-></c->

  <c- k><c- k>private</c-></c-><c- o><c- o>:</c-></c->
    <c- n><c- n>CompletionFunction</c-></c-> <c- n><c- n>completion</c-></c-><c- p><c- p>;</c-></c-> <i><c- c1><c- c1>// exposition only</c-></c-></i>
  <c- p><c- p>};</c-></c->
<c- p><c- p>}</c-></c->
</code></pre>
    <div class="numbered"> A <code class="highlight"><c- n>barrier</c-></code> is a barrier type with a <a data-link-type="dfn" href="#completion-step" id="ref-for-completion-step③">completion step</a> controlled by a function object. The <a data-link-type="dfn" href="#completion-step" id="ref-for-completion-step④">completion step</a> calls <code class="highlight"><c- n>completion</c-></code>. Threads may block at the barrier’s synchronization point for a <a data-link-type="dfn" href="#phases" id="ref-for-phases⑧">phase</a>, waiting for the expected sum contributions by threads that arrive in that <a data-link-type="dfn" href="#phases" id="ref-for-phases⑨">phase</a>. </div>
    <div class="numbered"> <code class="highlight"><c- n>CompletionFunction</c-></code> shall be <code class="highlight"><c- n>Cpp17MoveConstructible</c-></code> (Table <a href="http://eel.is/c++draft/utility.arg.requirements#tab:moveconstructible">26</a>), <code class="highlight"><c- n>is_invocable_r_v</c-><c- o>&lt;</c-><c- b>void</c-><c- p>,</c-> <c- n>CompletionFunction</c-><c- o>></c-></code> shall be <code class="highlight">true</code>, and <code class="highlight"><c- k>noexcept</c-><c- p>(</c-><c- n>declval</c-><c- o>&lt;</c-><c- n>CompletionFunction</c-><c- o>></c-><c- p>()())</c-></code> shall be <code class="highlight">true</code>. </div>
    <div class="numbered"> <code class="highlight"><c- n>barrier</c-><c- o>::</c-><c- n>arrival_token</c-></code> is an implementation-defined type. <code class="highlight"><c- n>is_nothrow_move_constructible_v</c-><c- o>&lt;</c-><c- n>barrier</c-><c- o>::</c-><c- n>arrival_token</c-><c- o>></c-></code> shall be <code class="highlight">true</code> and <code class="highlight"><c- n>is_nothrow_move_assignable_v</c-><c- o>&lt;</c-><c- n>barrier</c-><c- o>::</c-><c- n>arrival_token</c-><c- o>></c-></code> shall be <code class="highlight">true</code>. </div>
<pre class="highlight"><c- k>constexpr</c-> <c- k>explicit</c-> <c- nf>barrier</c-><c- p>(</c-><c- b>ptrdiff_t</c-> <c- n>expected</c-><c- p>,</c->
                           <c- n>CompletionFunction</c-> <c- n>f</c-> <c- o>=</c-> <c- n>CompletionFunction</c-><c- p>());</c->
</pre>
    <div class="numbered"> <em>Requires:</em> <code class="highlight"><c- n>expected</c-> <c- o>>=</c-> <c- mi>0</c-></code>, and <code class="highlight"><c- k>noexcept</c-><c- p>(</c-><c- n>f</c-><c- p>())</c-></code> shall be <code class="highlight">true</code>. </div>
    <div class="numbered"> <em>Effects:</em> Initializes the barrier for <code class="highlight"><c- n>expected</c-></code> number of threads in the first <a data-link-type="dfn" href="#phases" id="ref-for-phases①⓪">phase</a>, and initializes <code class="highlight"><c- n>completion</c-></code> with <code class="highlight"><c- n>move</c-><c- p>(</c-><c- n>f</c-><c- p>)</c-></code>. [ <em>Note:</em> If <code class="highlight"><c- n>expected</c-></code> is <code class="highlight"><c- mi>0</c-></code> this object may only be destroyed. — <em>end note</em> ] </div>
    <div class="numbered"> <em>Throws:</em> Any exception thrown by <code class="highlight"><c- n>CompletionFunction</c-></code>'s move constructor. </div>
<pre class="highlight"><c- o>~</c-><c- n>barrier</c-><c- p>();</c->
</pre>
    <div class="numbered"> <em>Requires:</em> No threads are blocked at a synchronization point for any <a data-link-type="dfn" href="#phases" id="ref-for-phases①①">phase</a>. </div>
    <div class="numbered"> <em>Effects:</em> Destroys the barrier. </div>
    <div class="numbered"> <em>Remarks:</em> May be called even if some threads have not yet returned from functions that block at a synchronization point, provided that they have unblocked. [ <em>Note:</em> The destructor may block until all threads have exited invocations of wait() on this object. — <em>end note</em> ] </div>
<pre class="highlight"><c- p>[[</c-><c- n>nodiscard</c-><c- p>]]</c-> <c- n>arrival_token</c-> <c- n>arrive</c-><c- p>(</c-><c- b>ptrdiff_t</c-> <c- n>update</c-> <c- o>=</c-> <c- mi>1</c-><c- p>);</c->
</pre>
    <div class="numbered"> <em>Requires:</em> The expected count is not less than <code class="highlight"><c- n>update</c-></code>. </div>
    <div class="numbered"> <em>Effects:</em> Constructs an object of type <code class="highlight"><c- n>arrival_token</c-></code> that is associated with the <code class="highlight"><c- n>barrier</c-></code>'s synchronization point for the current <a data-link-type="dfn" href="#phases" id="ref-for-phases①②">phase</a>, then arrives <code class="highlight"><c- n>update</c-></code> times at the synchronization point for the current <a data-link-type="dfn" href="#phases" id="ref-for-phases①③">phase</a>. </div>
    <div class="numbered"> <em>Synchronization:</em> The call to <code class="highlight"><c- n>arrive</c-></code> strongly happens before the start of the <a data-link-type="dfn" href="#completion-step" id="ref-for-completion-step⑤">completion step</a> for the current <a data-link-type="dfn" href="#phases" id="ref-for-phases①④">phase</a>. </div>
    <div class="numbered"> <em>Returns:</em> The constructed object. </div>
    <div class="numbered"> <em>Throws:</em> <code class="highlight"><c- n>system_error</c-></code> when an exception is required (<a href="http://eel.is/c++draft/thread.req.exception">31.2.2</a>). </div>
    <div class="numbered"> <em>Remarks:</em> This may cause the <a data-link-type="dfn" href="#completion-step" id="ref-for-completion-step⑥">completion step</a> to start. </div>
<pre class="highlight"><c- b>void</c-> <c- nf>wait</c-><c- p>(</c-><c- n>arrival_token</c-><c- o>&amp;&amp;</c-> <c- n>arrival</c-><c- p>)</c-> <c- k>const</c-><c- p>;</c->
</pre>
    <div class="numbered"> <em>Requires:</em> <code class="highlight"><c- n>arrival</c-></code> is associated with a synchronization point for the current or the immediately preceding <a data-link-type="dfn" href="#phases" id="ref-for-phases①⑤">phases</a> of the <code class="highlight"><c- n>barrier</c-></code>. </div>
    <div class="numbered"> <em>Effects:</em> Blocks at the synchronization point associated with <code class="highlight"><c- n>std</c-><c- o>::</c-><c- n>move</c-><c- p>(</c-><c- n>arrival</c-><c- p>)</c-></code> until the condition is satisfied. </div>
    <div class="numbered"> <em>Throws:</em> <code class="highlight"><c- n>system_error</c-></code> when an exception is required (<a href="http://eel.is/c++draft/thread.req.exception">31.2.2</a>). </div>
<pre class="highlight"><c- b>void</c-> <c- nf>arrive_and_wait</c-><c- p>();</c->
</pre>
    <div class="numbered"> <em>Effects:</em> Equivalent to <code class="highlight"><c- n>wait</c-><c- p>(</c-><c- n>arrive</c-><c- p>())</c-></code>. </div>
    <div class="numbered"> <em>Throws:</em> <code class="highlight"><c- n>system_error</c-></code> when an exception is required (<a href="http://eel.is/c++draft/thread.req.exception">31.2.2</a>). </div>
<pre class="highlight"><c- b>void</c-> <c- nf>arrive_and_drop</c-><c- p>();</c->
</pre>
    <div class="numbered"> <em>Requires:</em> The expected number of threads for the current <a data-link-type="dfn" href="#phases" id="ref-for-phases①⑥">phase</a> is not <code class="highlight"><c- mi>0</c-></code>. </div>
    <div class="numbered"> <em>Effects:</em> Decrements the expected number of threads for subsequent <a data-link-type="dfn" href="#phases" id="ref-for-phases①⑦">phases</a> by <code class="highlight"><c- mi>1</c-></code>, then arrives at the synchronization point for the current <a data-link-type="dfn" href="#phases" id="ref-for-phases①⑧">phase</a>. </div>
    <div class="numbered"> <em>Synchronization:</em> The call to <code class="highlight"><c- n>arrive_and_drop</c-></code> strongly happens before the start of the <a data-link-type="dfn" href="#completion-step" id="ref-for-completion-step⑦">completion step</a> for the current <a data-link-type="dfn" href="#phases" id="ref-for-phases①⑨">phase</a>. </div>
    <div class="numbered"> <em>Throws:</em> <code class="highlight"><c- n>system_error</c-></code> when an exception is required (<a href="http://eel.is/c++draft/thread.req.exception">31.2.2</a>). </div>
    <div class="numbered"> <em>Remarks:</em> This may cause the <a data-link-type="dfn" href="#completion-step" id="ref-for-completion-step⑧">completion step</a> to start. </div>
   </blockquote>
   <p>Create the following feature test macros:</p>
   <ul>
    <li data-md>
     <p><code class="highlight"><c- n>__cpp_lib_atomic_lock_free_type_aliases</c-></code>, which implies that <code class="highlight"><c- n>atomic_signed_lock_free</c-></code> and <code class="highlight"><c- n>atomic_unsigned_lock_free</c-></code> types are available.</p>
    <li data-md>
     <p><code class="highlight"><c- n>__cpp_lib_atomic_flag_test</c-></code>, which implies the <code class="highlight"><c- n>test</c-></code> methods and free functions for <code class="highlight"><c- n>atomic_flag</c-></code> are available.</p>
    <li data-md>
     <p><code class="highlight"><c- n>__cpp_lib_atomic_wait</c-></code>, which implies the <code class="highlight"><c- n>notify_</c-><c- o>*</c-></code> and <code class="highlight"><c- n>wait</c-></code> methods and free functions for <code class="highlight"><c- n>atomic</c-></code> and <code class="highlight"><c- n>atomic_flag</c-></code> are available.</p>
    <li data-md>
     <p><code class="highlight"><c- n>__cpp_lib_semaphore</c-></code>, which implies that <code class="highlight"><c- n>counting_semaphore</c-></code> and <code class="highlight"><c- n>binary_semaphore</c-></code> are available.</p>
    <li data-md>
     <p><code class="highlight"><c- n>__cpp_lib_latch</c-></code>, which implies that <code class="highlight"><c- n>latch</c-></code> is available.</p>
    <li data-md>
     <p><code class="highlight"><c- n>__cpp_lib_barrier</c-></code>, which implies that <code class="highlight"><c- n>barrier</c-></code> is available.</p>
   </ul>
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  <h2 class="no-num no-ref heading settled" id="index"><span class="content">Index</span><a class="self-link" href="#index"></a></h2>
  <h3 class="no-num no-ref heading settled" id="index-defined-here"><span class="content">Terms defined by this specification</span><a class="self-link" href="#index-defined-here"></a></h3>
  <ul class="index">
   <li><a href="#atomic-notifying-operations">atomic notifying operations</a><span>, in §3</span>
   <li><a href="#atomic-waiting-and-notifying-operations">Atomic waiting and notifying operations</a><span>, in §3</span>
   <li><a href="#atomic-waiting-operations">atomic waiting operations</a><span>, in §3</span>
   <li><a href="#completion-step">completion step</a><span>, in §3</span>
   <li><a href="#coordination-types">coordination types</a><span>, in §3</span>
   <li><a href="#phases">phases</a><span>, in §3</span>
  </ul>
  <h2 class="no-num no-ref heading settled" id="references"><span class="content">References</span><a class="self-link" href="#references"></a></h2>
  <h3 class="no-num no-ref heading settled" id="informative"><span class="content">Informative References</span><a class="self-link" href="#informative"></a></h3>
  <dl>
   <dt id="biblio-n4791">[N4791]
   <dd>Richard Smith. <a href="https://wg21.link/n4791">Working Draft, Standard for Programming Language C++</a>. 26 November 2018. URL: <a href="https://wg21.link/n4791">https://wg21.link/n4791</a>
   <dt id="biblio-p0514r4">[P0514R4]
   <dd>Olivier Giroux. <a href="https://wg21.link/p0514r4">Efficient concurrent waiting for C++20</a>. 3 May 2018. URL: <a href="https://wg21.link/p0514r4">https://wg21.link/p0514r4</a>
   <dt id="biblio-p0666r2">[P0666R2]
   <dd>Olivier Giroux. <a href="https://wg21.link/p0666r2">Revised Latches and Barriers for C++20</a>. 6 May 2018. URL: <a href="https://wg21.link/p0666r2">https://wg21.link/p0666r2</a>
   <dt id="biblio-p0995r1">[P0995R1]
   <dd>JF Bastien, Olivier Giroux, Andrew Hunter. <a href="https://wg21.link/p0995r1">Improving atomic_flag</a>. 22 June 2018. URL: <a href="https://wg21.link/p0995r1">https://wg21.link/p0995r1</a>
   <dt id="biblio-p1258r0">[P1258R0]
   <dd>Detlef Vollmann. <a href="https://wg21.link/p1258r0">Don't Make C++ Unimplementable On Small CPUs</a>. 8 October 2018. URL: <a href="https://wg21.link/p1258r0">https://wg21.link/p1258r0</a>
  </dl>
  <aside class="dfn-panel" data-for="atomic-waiting-and-notifying-operations">
   <b><a href="#atomic-waiting-and-notifying-operations">#atomic-waiting-and-notifying-operations</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-atomic-waiting-and-notifying-operations">3. Wording</a> <a href="#ref-for-atomic-waiting-and-notifying-operations①">(2)</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="atomic-waiting-operations">
   <b><a href="#atomic-waiting-operations">#atomic-waiting-operations</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-atomic-waiting-operations">3. Wording</a> <a href="#ref-for-atomic-waiting-operations①">(2)</a> <a href="#ref-for-atomic-waiting-operations②">(3)</a> <a href="#ref-for-atomic-waiting-operations③">(4)</a> <a href="#ref-for-atomic-waiting-operations④">(5)</a> <a href="#ref-for-atomic-waiting-operations⑤">(6)</a> <a href="#ref-for-atomic-waiting-operations⑥">(7)</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="atomic-notifying-operations">
   <b><a href="#atomic-notifying-operations">#atomic-notifying-operations</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-atomic-notifying-operations">3. Wording</a> <a href="#ref-for-atomic-notifying-operations①">(2)</a> <a href="#ref-for-atomic-notifying-operations②">(3)</a> <a href="#ref-for-atomic-notifying-operations③">(4)</a> <a href="#ref-for-atomic-notifying-operations④">(5)</a> <a href="#ref-for-atomic-notifying-operations⑤">(6)</a> <a href="#ref-for-atomic-notifying-operations⑥">(7)</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="coordination-types">
   <b><a href="#coordination-types">#coordination-types</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-coordination-types">3. Wording</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="phases">
   <b><a href="#phases">#phases</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-phases">3. Wording</a> <a href="#ref-for-phases①">(2)</a> <a href="#ref-for-phases②">(3)</a> <a href="#ref-for-phases③">(4)</a> <a href="#ref-for-phases④">(5)</a> <a href="#ref-for-phases⑤">(6)</a> <a href="#ref-for-phases⑥">(7)</a> <a href="#ref-for-phases⑦">(8)</a> <a href="#ref-for-phases⑧">(9)</a> <a href="#ref-for-phases⑨">(10)</a> <a href="#ref-for-phases①⓪">(11)</a> <a href="#ref-for-phases①①">(12)</a> <a href="#ref-for-phases①②">(13)</a> <a href="#ref-for-phases①③">(14)</a> <a href="#ref-for-phases①④">(15)</a> <a href="#ref-for-phases①⑤">(16)</a> <a href="#ref-for-phases①⑥">(17)</a> <a href="#ref-for-phases①⑦">(18)</a> <a href="#ref-for-phases①⑧">(19)</a> <a href="#ref-for-phases①⑨">(20)</a>
   </ul>
  </aside>
  <aside class="dfn-panel" data-for="completion-step">
   <b><a href="#completion-step">#completion-step</a></b><b>Referenced in:</b>
   <ul>
    <li><a href="#ref-for-completion-step">3. Wording</a> <a href="#ref-for-completion-step①">(2)</a> <a href="#ref-for-completion-step②">(3)</a> <a href="#ref-for-completion-step③">(4)</a> <a href="#ref-for-completion-step④">(5)</a> <a href="#ref-for-completion-step⑤">(6)</a> <a href="#ref-for-completion-step⑥">(7)</a> <a href="#ref-for-completion-step⑦">(8)</a> <a href="#ref-for-completion-step⑧">(9)</a>
   </ul>
  </aside>
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        el.style.left = null;
        el.style.top = null;
    }

});
</script>