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 <head>
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  <title>P1152R2: Deprecating &lt;code>volatile&lt;/code></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,
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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">P1152R2<br>Deprecating <code class="highlight"><c- k>volatile</c-></code></h1>
   <h2 class="no-num no-toc no-ref heading settled" id="subtitle"><span class="content">Published Proposal, <time class="dt-updated" datetime="2019-03-09">2019-03-09</time></span></h2>
   <div data-fill-with="spec-metadata">
    <dl>
     <dt>This version:
     <dd><a class="u-url" href="http://wg21.link/P1152R2">http://wg21.link/P1152R2</a>
     <dt>Author:
     <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>)
     <dt>Audience:
     <dd>LEWG, CWG, LWG
     <dt>Project:
     <dd>ISO/IEC JTC1/SC22/WG21 14882: Programming Language — C++
     <dt>Source:
     <dd><a href="https://github.com/jfbastien/papers/blob/master/source/P1152R2.bs">github.com/jfbastien/papers/blob/master/source/P1152R2.bs</a>
    </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="#abstract"><span class="secno">1</span> <span class="content">Abstract</span></a>
    <li>
     <a href="#edit"><span class="secno">2</span> <span class="content">Edit History</span></a>
     <ol class="toc">
      <li><a href="#r1r2"><span class="secno">2.1</span> <span class="content">r1 → r2</span></a>
      <li><a href="#r0r1"><span class="secno">2.2</span> <span class="content">r0 → r1</span></a>
     </ol>
    <li>
     <a href="#word"><span class="secno">3</span> <span class="content">Wording</span></a>
     <ol class="toc">
      <li><a href="#intro.execution"><span class="secno">3.1</span> <span class="content">Program execution [<strong>intro.execution</strong>]</span></a>
      <li><a href="#data.races"><span class="secno">3.2</span> <span class="content">Data races [<strong>intro.races</strong>]</span></a>
      <li><a href="#intro.progress"><span class="secno">3.3</span> <span class="content">Forward progress [<strong>intro.progress</strong>]</span></a>
      <li><a href="#expr.post.incr"><span class="secno">3.4</span> <span class="content">Increment and decrement [<strong>expr.post.incr</strong>]</span></a>
      <li><a href="#expr.ref"><span class="secno">3.5</span> <span class="content">Class member access [<strong>expr.ref</strong>]</span></a>
      <li><a href="#expr.pre.incr"><span class="secno">3.6</span> <span class="content">Increment and decrement [<strong>expr.pre.incr</strong>]</span></a>
      <li><a href="#expr.ass"><span class="secno">3.7</span> <span class="content">Assignment and compound assignment operators [<strong>expr.ass</strong>]</span></a>
      <li><a href="#dcl.type.cv"><span class="secno">3.8</span> <span class="content">The cv-qualifiers [<strong>dcl.type.cv</strong>]</span></a>
      <li><a href="#dcl.fct"><span class="secno">3.9</span> <span class="content">Functions [<strong>dcl.fct</strong>]</span></a>
      <li><a href="#class.mfct.non-static"><span class="secno">3.10</span> <span class="content">Non-static member functions [<strong>class.mfct.non-static</strong>]</span></a>
      <li><a href="#class.this"><span class="secno">3.11</span> <span class="content">The this pointer [<strong>class.this</strong>]</span></a>
      <li><a href="#class.ctor"><span class="secno">3.12</span> <span class="content">Constructors [<strong>class.ctor</strong>]</span></a>
      <li><a href="#class.dtor"><span class="secno">3.13</span> <span class="content">Destructors [<strong>class.dtor</strong>]</span></a>
      <li><a href="#over.load"><span class="secno">3.14</span> <span class="content">Overloadable declarations [<strong>over.load</strong>]</span></a>
      <li><a href="#over.built"><span class="secno">3.15</span> <span class="content">Built-in operators [<strong>over.built</strong>]</span></a>
      <li><a href="#tuple"><span class="secno">3.16</span> <span class="content">Tuples [<strong>tuple</strong>]</span></a>
      <li><a href="#variant"><span class="secno">3.17</span> <span class="content">Variants [<strong>variant</strong>]</span></a>
      <li><a href="#atomics"><span class="secno">3.18</span> <span class="content">Atomic operations library [<strong>atomics</strong>]</span></a>
      <li><a href="#annexD"><span class="secno">3.19</span> <span class="content">Annex D</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="abstract"><span class="secno">1. </span><span class="content">Abstract</span><a class="self-link" href="#abstract"></a></h2>
   <p>We propose deprecating most of <code class="highlight"><c- k>volatile</c-></code>. See <a href="#word">§3 Wording</a> for the details.</p>
   <p>The proposed deprecation preserves the useful parts of <code class="highlight"><c- k>volatile</c-></code>, and removes
the dubious / already broken ones. This paper aims at breaking at compile-time
code which is today subtly broken at runtime or through a compiler update. The
paper might also break another type of code: that which doesn’t exist. This
removes a significant foot-gun and removes unintuitive corner cases from the
languages.</p>
   <p>The first version of this paper, <a data-link-type="biblio" href="#biblio-p1152r0">[P1152R0]</a>, has extensive background
information which is not repeated here:</p>
   <ul>
    <li data-md>
     <p><a href="wg21.link/P1152R0#over">Overview</a></p>
    <li data-md>
     <p><a href="wg21.link/P1152R0#where">How we got here</a></p>
    <li data-md>
     <p><a href="wg21.link/P1152R0#why">Why the proposed changes?</a></p>
    <li data-md>
     <p><a href="wg21.link/P1152R0#examples">Examples</a></p>
   </ul>
   <p>See <a data-link-type="biblio" href="#biblio-p1382r0">[P1382R0]</a> for the follow-up paper on <code class="highlight"><c- n>volatile_load</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> / <code class="highlight"><c- n>volatile_store</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> requested by SG1.</p>
   <h2 class="heading settled" data-level="2" id="edit"><span class="secno">2. </span><span class="content">Edit History</span><a class="self-link" href="#edit"></a></h2>
   <h3 class="heading settled" data-level="2.1" id="r1r2"><span class="secno">2.1. </span><span class="content">r1 → r2</span><a class="self-link" href="#r1r2"></a></h3>
   <p><a data-link-type="biblio" href="#biblio-p1152r1">[P1152R1]</a> was seen by SG1 and EWG in Kona. This update does the following:</p>
   <ul>
    <li data-md>
     <p>Also edit sections [<strong>expr.post.incr</strong>], [<strong>expr.pre.incr</strong>], [<strong>expr.ass</strong>], which are redundant with other sections already modified by this paper.</p>
    <li data-md>
     <p>Change <em>Remarks</em> to <em>Constraints</em> per <a data-link-type="biblio" href="#biblio-p1369r0">[P1369R0]</a>.</p>
    <li data-md>
     <p>Change language wording to explicitly call out deprecation.</p>
   </ul>
   <table>
    <thead>
     <tr>
      <th>Poll
      <th>Group
      <th>SF
      <th>F
      <th>N
      <th>A
      <th>SA
      <th>Outcome
    <tbody>
     <tr>
      <th>Forward this paper—with edits as discussed—to EWG for C++20.
      <th>SG1
      <th>3
      <th>12
      <th>1
      <th>1
      <th>0
      <th>✅
     <tr>
      <th>Proposal as presented for C++20.
      <th>EWG
      <th>6
      <th>27
      <th>1
      <th>0
      <th>0
      <th>✅
   </table>
   <h3 class="heading settled" data-level="2.2" id="r0r1"><span class="secno">2.2. </span><span class="content">r0 → r1</span><a class="self-link" href="#r0r1"></a></h3>
   <p><a data-link-type="biblio" href="#biblio-p1152r0">[P1152R0]</a> was seen by SG1 and EWG in San Diego. This update does the
following:</p>
   <ul>
    <li data-md>
     <p>Remove background information from the paper.</p>
    <li data-md>
     <p>Follow the guidance from SG1 and EWG, based on the polls below.</p>
   </ul>
   <table>
    <thead>
     <tr>
      <th>Poll
      <th>Group
      <th>SF
      <th>F
      <th>N
      <th>A
      <th>SA
      <th>Outcome
    <tbody>
     <tr>
      <th>Deprecate <code class="highlight"><c- k>volatile</c-></code> compound operations (including <code class="highlight"><c- o>++</c-></code> and <code class="highlight"><c- o>--</c-></code>) on scalar types (arithmetic, pointer, enumeration).
      <th>SG1
      <th>4
      <th>19
      <th>3
      <th>0
      <th>0
      <th>✅
     <tr>
      <th>Deprecate <code class="highlight"><c- k>volatile</c-></code> compound operations (including <code class="highlight"><c- o>++</c-></code> and <code class="highlight"><c- o>--</c-></code>) on scalar types (arithmetic, pointer, enumeration).
      <th>EWG
      <th>4
      <th>9
      <th>4
      <th>0
      <th>0
      <th>✅
     <tr>
      <th>Deprecate usage of <code class="highlight"><c- k>volatile</c-></code> assignment chaining on scalar types (arithmetic, pointer, enumeration, pointer to members, <code class="highlight"><c- n>nullptr_t</c-></code>).
      <th>SG1
      <th>6
      <th>15
      <th>3
      <th>0
      <th>0
      <th>✅
     <tr>
      <th>Deprecate usage of <code class="highlight"><c- k>volatile</c-></code> assignment chaining on scalar types (arithmetic, pointer, enumeration, pointer to members, <code class="highlight"><c- n>nullptr_t</c-></code>).
      <th>EWG
      <th>6
      <th>9
      <th>3
      <th>0
      <th>0
      <th>✅
     <tr>
      <th>SG1 would be OK if we deprecated <code class="highlight"><c- k>volatile</c-></code> qualified member functions (pending separate decision on what we do with <code class="highlight"><c- k>volatile</c-></code> atomic).
      <th>SG1
      <th>1
      <th>5
      <th>10
      <th>4
      <th>3
      <th>❌
     <tr>
      <th>EWG would be OK if we deprecated <code class="highlight"><c- k>volatile</c-></code> qualified member functions (pending separate decision on what we do with <code class="highlight"><c- k>volatile</c-></code> atomic).
      <th>EWG
      <th>2
      <th>7
      <th>7
      <th>1
      <th>0
      <th>✅
     <tr>
      <th>SG1 would be OK if we deprecated <code class="highlight"><c- k>volatile</c-></code> partial template specializations, overloads, or qualified member functions in the STL for all but the atomic, <code class="highlight"><c- n>numeric_limits</c-></code>, and type traits (<code class="highlight"><c- n>remove_volatile</c-></code>, <code class="highlight"><c- n>add_volatile</c-></code>, etc) parts of the Library.
      <th>SG1
      <th>1
      <th>9
      <th>6
      <th>2
      <th>0
      <th>✅
     <tr>
      <th>EWG would be OK if we deprecated <code class="highlight"><c- k>volatile</c-></code> partial template specializations, overloads, or qualified member functions in the STL for all but the atomic, <code class="highlight"><c- n>numeric_limits</c-></code>, and type traits (<code class="highlight"><c- n>remove_volatile</c-></code>, <code class="highlight"><c- n>add_volatile</c-></code>, etc) parts of the Library.
      <th>EWG
      <th>1
      <th>11
      <th>9
      <th>0
      <th>0
      <th>✅
     <tr>
      <th>Deprecate <code class="highlight"><c- k>volatile</c-></code> member functions of atomic in favor of new template partial specializations which will only declare load, store, and only exist when <code class="highlight"><c- n>is_always_lock_free</c-></code> is true.
      <th>SG1
      <th>2
      <th>1
      <th>1
      <th>11
      <th>2
      <th>❌
     <tr>
      <th>Deprecate <code class="highlight"><c- k>volatile</c-></code> member functions of atomic in favor of new template partial specializations which will only declare load, store, RMW, and only exist when <code class="highlight"><c- n>is_always_lock_free</c-></code> is true.
      <th>SG1
      <th>4
      <th>7
      <th>3
      <th>3
      <th>0
      <th>✅
     <tr>
      <th>Deprecate <code class="highlight"><c- k>volatile</c-></code> member functions of atomic in favor of new template partial specializations which will only declare load, store, RMW, and only exist when <code class="highlight"><c- n>is_always_lock_free</c-></code> is true.
      <th>EWG
      <th>2
      <th>9
      <th>3
      <th>0
      <th>0
      <th>✅
     <tr>
      <th>Deprecate <code class="highlight"><c- k>volatile</c-></code> member functions of atomic in favor of new template partial specializations which will only declare load, store, RMW.
      <th>SG1
      <th>0
      <th>0
      <th>0
      <th>10
      <th>7
      <th>❌
     <tr>
      <th>SG1 would be OK if we deprecated top-level <code class="highlight"><c- k>volatile</c-></code> parameters.
      <th>SG1
      <th>6
      <th>9
      <th>6
      <th>2
      <th>1
      <th>✅
     <tr>
      <th>EWG would be OK if we deprecated top-level <code class="highlight"><c- k>volatile</c-></code> parameters.
      <th>EWG
      <th>6
      <th>9
      <th>6
      <th>0
      <th>0
      <th>✅
     <tr>
      <th>EWG would be OK if we deprecated top-level const parameters.
      <th>EWG
      <th>0
      <th>2
      <th>5
      <th>8
      <th>8
      <th>❌
     <tr>
      <th>SG1 would be OK if we deprecated top-level <code class="highlight"><c- k>volatile</c-></code> return values.
      <th>SG1
      <th>6
      <th>9
      <th>4
      <th>2
      <th>0
      <th>✅
     <tr>
      <th>EWG would be OK if we deprecated top-level <code class="highlight"><c- k>volatile</c-></code> return values.
      <th>EWG
      <th>6
      <th>6
      <th>5
      <th>0
      <th>0
      <th>✅
     <tr>
      <th>EWG would be OK if we deprecated top-level const return values.
      <th>EWG
      <th>2
      <th>3
      <th>3
      <th>5
      <th>5
      <th>❌
     <tr>
      <th>SG1 interested is interested in hearing about <code class="highlight"><c- n>volatile_load</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> / <code class="highlight"><c- n>volatile_store</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> free functions in a separate paper, given that time is limited and we could be doing something else.
      <th>SG1
      <th>0
      <th>17
      <th>4
      <th>3
      <th>0
      <th>✅
     <tr>
      <th>EWG interested is interested in hearing about <code class="highlight"><c- n>volatile_load</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> / <code class="highlight"><c- n>volatile_store</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> free functions in a separate paper, given that time is limited and we could be doing something else.
      <th>EWG
      <th>2
      <th>11
      <th>4
      <th>1
      <th>0
      <th>✅
   </table>
   <h2 class="heading settled" data-level="3" id="word"><span class="secno">3. </span><span class="content">Wording</span><a class="self-link" href="#word"></a></h2>
   <p>The proposed wording follows the language and library approach to deprecation:</p>
   <ul>
    <li data-md>
     <p>Language deprecation is called out in the Standard text itself, and repeated
in Annex D.</p>
    <li data-md>
     <p>Library deprecation presents the library without the deprecated feature, and
only mentions said feature in Annex D.</p>
   </ul>
   <h3 class="heading settled" data-level="3.1" id="intro.execution"><span class="secno">3.1. </span><span class="content">Program execution [<strong>intro.execution</strong>]</span><a class="self-link" href="#intro.execution"></a></h3>
   <p>No changes.</p>
   <blockquote>
    <p>Accesses through <code class="highlight"><c- k>volatile</c-></code> glvalues are evaluated strictly according to the
  rules of the abstract machine.</p>
    <p>Reading an object designated by a <code class="highlight"><c- k>volatile</c-></code> glvalue, modifying an object,
  calling a library I/O function, or calling a function that does any of those
  operations are all <em>side effects</em>, which are changes in the state of the
  execution environment. <em>Evaluation</em> of an expression (or a subexpression) in
  general includes both value computations (including determining the identity
  of an object for glvalue evaluation and fetching a value previously assigned
  to an object for prvalue evaluation) and initiation of side effects. When a
  call to a library I/O function returns or an access through a <code class="highlight"><c- k>volatile</c-></code> glvalue is evaluated the side effect is considered complete, even though some
  external actions implied by the call (such as the I/O itself) or by the <code class="highlight"><c- k>volatile</c-></code> access may not have completed yet.</p>
   </blockquote>
   <h3 class="heading settled" data-level="3.2" id="data.races"><span class="secno">3.2. </span><span class="content">Data races [<strong>intro.races</strong>]</span><a class="self-link" href="#data.races"></a></h3>
   <p>No changes.</p>
   <blockquote>
    <p>Two accesses to the same object of type <code class="highlight"><c- k>volatile</c-></code> <code class="highlight"><c- n>std</c-><c- o>::</c-><c- b>sig_atomic_t</c-></code> do not
  result in a data race if both occur in the same thread, even if one or more
  occurs in a signal handler. For each signal handler invocation, evaluations
  performed by the thread invoking a signal handler can be divided into two
  groups A and B, such that no evaluations in B happen before evaluations in A,
  and the evaluations of such <code class="highlight"><c- k>volatile</c-></code> <code class="highlight"><c- n>std</c-><c- o>::</c-><c- b>sig_atomic_t</c-></code> objects take values
  as though all evaluations in A happened before the execution of the signal
  handler and the execution of the signal handler happened before all
  evaluations in B.</p>
   </blockquote>
   <h3 class="heading settled" data-level="3.3" id="intro.progress"><span class="secno">3.3. </span><span class="content">Forward progress [<strong>intro.progress</strong>]</span><a class="self-link" href="#intro.progress"></a></h3>
   <p>No changes.</p>
   <blockquote>
    <p>The implementation may assume that any thread will eventually do one of the
  following:</p>
    <ul>
     <li data-md>
      <p>terminate,</p>
     <li data-md>
      <p>make a call to a library I/O function,</p>
     <li data-md>
      <p>perform an access through a <code class="highlight"><c- k>volatile</c-></code> glvalue, or</p>
     <li data-md>
      <p>perform a synchronization operation or an atomic operation</p>
    </ul>
    <p>During the execution of a thread of execution, each of the following is termed
  an execution step:</p>
    <ul>
     <li data-md>
      <p>termination of the thread of execution,</p>
     <li data-md>
      <p>performing an access through a <code class="highlight"><c- k>volatile</c-></code> glvalue, or</p>
     <li data-md>
      <p>completion of a call to a library I/O function, a synchronization
operation, or an atomic operation.</p>
    </ul>
   </blockquote>
   <h3 class="heading settled" data-level="3.4" id="expr.post.incr"><span class="secno">3.4. </span><span class="content">Increment and decrement [<strong>expr.post.incr</strong>]</span><a class="self-link" href="#expr.post.incr"></a></h3>
   <p>Modify as follows.</p>
   <blockquote>
    <p>
     The value of a postfix <code class="highlight"><c- o>++</c-></code> expression is the value of its operand. [ <em>Note:</em> The value obtained is a copy of the original value —<em>end note</em> ] The operand
  shall be a modifiable lvalue. The type of the operand shall be 
     <del>an
  arithmetic type other than <em>cv</em> <code class="highlight"><c- b>bool</c-></code></del>
     <ins>a non-<code class="highlight"><c- k>volatile</c-></code> qualified
  arithmetic type other than <code class="highlight"><c- b>bool</c-></code></ins>
     , or a 
     <ins>non-<code class="highlight"><c- k>volatile</c-></code> qualified </ins>
      pointer to a complete object type. 
     <ins>The type of the operand can be a <code class="highlight"><c- k>volatile</c-></code>-qualified
  arithmetic type other than <em>cv</em> <code class="highlight"><c- b>bool</c-></code>, or a <code class="highlight"><c- k>volatile</c-></code>-qualified
  pointer to a complete object type (this usage is deprecated; see [<strong>depr.volatile</strong>]).</ins>
      The value of the operand object is
  modified by adding <code class="highlight"><c- mi>1</c-></code> to it. The value computation of the <code class="highlight"><c- o>++</c-></code> expression is
  sequenced before the modification of the operand object. With respect to an
  indeterminately-sequenced function call, the operation of postfix <code class="highlight"><c- o>++</c-></code> is a
  single evaluation. [ <em>Note:</em> Therefore, a function call shall not intervene
  between the lvalue-to-rvalue conversion and the side effect associated with
  any single postfix <code class="highlight"><c- o>++</c-></code> operator. —<em>end note</em> ] The result is a prvalue. The
  type of the result is the <em>cv</em>-unqualified version of the type of the operand.
  If the operand is a bit-field that cannot represent the incremented value, the
  resulting value of the bit-field is implementation-defined. See also
  [<strong>expr.add</strong>] and [<strong>expr.ass</strong>].
    </p>
    <p>The operand of postfix <code class="highlight"><c- o>--</c-></code> is decremented analogously to the postfix <code class="highlight"><c- o>++</c-></code> operator. [ <em>Note:</em> For prefix increment and decrement, see
  [<strong>expr.pre.incr</strong>]. —<em>end note</em> ]</p>
   </blockquote>
   <h3 class="heading settled" data-level="3.5" id="expr.ref"><span class="secno">3.5. </span><span class="content">Class member access [<strong>expr.ref</strong>]</span><a class="self-link" href="#expr.ref"></a></h3>
   <p>No changes.</p>
   <blockquote>
    <p>Abbreviating <em>postfix-expression.id-expression</em> as <code class="highlight"><c- n>E1</c-><c- p>.</c-><c- n>E2</c-></code>, <code class="highlight"><c- n>E1</c-></code> is called the <em>object expression</em>. If <code class="highlight"><c- n>E2</c-></code> is a bit-field, <code class="highlight"><c- n>E1</c-><c- p>.</c-><c- n>E2</c-></code> is a bit-field. The type
  and value category of <code class="highlight"><c- n>E1</c-><c- p>.</c-><c- n>E2</c-></code> are determined as follows. In the remainder of
  [<strong>expr.ref</strong>], <em>cq</em> represents either <code class="highlight"><c- k>const</c-></code> or the absence of <code class="highlight"><c- k>const</c-></code> and <em>vq</em> represents either <code class="highlight"><c- k>volatile</c-></code> or the absence of <code class="highlight"><c- k>volatile</c-></code>. <em>cv</em> represents an arbitrary set of cv-qualifiers.</p>
    <ul>
     <li data-md>
      <p>If <code class="highlight"><c- n>E2</c-></code> is a non-static data member and the type of <code class="highlight"><c- n>E1</c-></code> is “<em>cq1 vq1 X</em>”,
and the type of <code class="highlight"><c- n>E2</c-></code> is “<em>cq2 vq2 T</em>”, the expression designates the named
member of the object designated by the first expression. If <code class="highlight"><c- n>E1</c-></code> is an
lvalue, then <code class="highlight"><c- n>E1</c-><c- p>.</c-><c- n>E2</c-></code> is an lvalue; otherwise <code class="highlight"><c- n>E1</c-><c- p>.</c-><c- n>E2</c-></code> is an xvalue. Let the
notation <em>vq12</em> stand for the “union” of <em>vq1</em> and <em>vq2</em>; that is, if <em>vq1</em> or <em>vq2</em> is <code class="highlight"><c- k>volatile</c-></code>, then <em>vq12</em> is <code class="highlight"><c- k>volatile</c-></code>. Similarly, let the
notation <em>cq12</em> stand for the “union” of <em>cq1</em> and <em>cq2</em>; that is, if <em>cq1</em> or <em>cq2</em> is <code class="highlight"><c- k>const</c-></code>, then <em>cq12</em> is <code class="highlight"><c- k>const</c-></code>. If <code class="highlight"><c- n>E2</c-></code> is declared to be a <code class="highlight"><c- k>mutable</c-></code> member, then the type of <code class="highlight"><c- n>E1</c-><c- p>.</c-><c- n>E2</c-></code> is “<em>vq12 T</em>”. If <code class="highlight"><c- n>E2</c-></code> is not
declared to be a <code class="highlight"><c- k>mutable</c-></code> member, then the type of <code class="highlight"><c- n>E1</c-><c- p>.</c-><c- n>E2</c-></code> is
“<em>cq12 vq12 T</em>”.</p>
    </ul>
   </blockquote>
   <h3 class="heading settled" data-level="3.6" id="expr.pre.incr"><span class="secno">3.6. </span><span class="content">Increment and decrement [<strong>expr.pre.incr</strong>]</span><a class="self-link" href="#expr.pre.incr"></a></h3>
   <p>Modify as follows.</p>
   <blockquote>
    <p>
     The operand of prefix <code class="highlight"><c- o>++</c-></code> is modified by adding <code class="highlight"><c- mi>1</c-></code>. The operand shall be a
  modifiable lvalue. The type of the operand shall be 
     <del>an arithmetic type
  other than <em>cv</em> <code class="highlight"><c- b>bool</c-></code></del>
     <ins>a non-<code class="highlight"><c- k>volatile</c-></code>-qualified arithmetic type
  other than <code class="highlight"><c- b>bool</c-></code></ins>
     , or a 
     <ins>non-<code class="highlight"><c- k>volatile</c-></code>-qualified </ins>
     pointer to a
  completely-defined object type. 
     <ins>The type of the operand can be a <code class="highlight"><c- k>volatile</c-></code>-qualified arithmetic type
  other than <em>cv</em> <code class="highlight"><c- b>bool</c-></code>, or a <code class="highlight"><c- k>volatile</c-></code>-qualified pointer to a
  completely-defined object type (this usage is deprecated; see [<strong>depr.volatile</strong>]).</ins>
      The result is the updated operand; it is an
  lvalue, and it is a bit-field if the operand is a bit-field. The expression <code class="highlight"><c- o>++</c-><c- n>x</c-></code> is equivalent to <code class="highlight"><c- n>x</c-><c- o>+=</c-><c- mi>1</c-></code>. [ <em>Note:</em> See the discussions of [<strong>expr.add</strong>]
  and assignment operators [<strong>expr.ass</strong>] for information on conversions. —<em>end
  note</em> ]
    </p>
    <p>The operand of prefix <code class="highlight"><c- o>--</c-></code> is modified by subtracting <code class="highlight"><c- mi>1</c-></code>. The requirements on
  the operand of prefix <code class="highlight"><c- o>--</c-></code> and the properties of its result are otherwise the
  same as those of prefix <code class="highlight"><c- o>++</c-></code>. [ <em>Note:</em> For postfix increment and decrement,
  see [<strong>expr.post.incr</strong>]. —<em>end note</em> ]</p>
   </blockquote>
   <h3 class="heading settled" data-level="3.7" id="expr.ass"><span class="secno">3.7. </span><span class="content">Assignment and compound assignment operators [<strong>expr.ass</strong>]</span><a class="self-link" href="#expr.ass"></a></h3>
   <p>Modify as follows.</p>
   <blockquote>
    <ol>
     <li> The assignment operator (<code class="highlight"><c- o>=</c-></code>) and the compound assignment operators all group
  right-to-left. 
     <li>
       All require a modifiable lvalue as their left operand; their result is an
  lvalue referring to the left operand. The result in all cases is a bit-field
  if the left operand is a bit-field. In all cases, the assignment is sequenced
  after the value computation of the right and left operands, and before the
  value computation of the assignment expression. The right operand is sequenced
  before the left operand. With respect to an indeterminately-sequenced function
  call, the operation of a compound assignment is a single evaluation. [ <em>Note:</em> Therefore, a function call shall not intervene between the lvalue-to-rvalue
  conversion and the side effect associated with any single compound assignment
  operator. —<em>end note</em> ] 
<pre class="highlight"><em><c- n>assignment</c-><c- o>-</c-><c- n>expression</c-></em>
    <em><c- n>conditional</c-><c- o>-</c-><c- n>expression</c-></em>
    <em><c- n>logical</c-><c- o>-</c-><c- n>or</c-><c- o>-</c-><c- n>expression</c-> <c- n>assignment</c-><c- o>-</c-><c- k>operator</c-> <c- n>initializer</c-><c- o>-</c-><c- n>clause</c-></em>
    <em><c- k>throw</c-><c- o>-</c-><c- n>expression</c-></em>

<em><c- n>assignment</c-><c- o>-</c-><c- k>operator</c-></em><c- o>:</c-> <c- n>one</c-> <c- n>of</c->
    <code class="highlight"><c- o><c- o>=</c-></c->  <c- o><c- o>*=</c-></c->  <c- o><c- o>/=</c-></c->  <c- o><c- o>%=</c-></c->   <c- o><c- o>+=</c-></c->  <c- o><c- o>-=</c-></c->  <c- o><c- o>>>=</c-></c->  <c- o><c- o>&lt;&lt;=</c-></c->  <c- o><c- o>&amp;=</c-></c->  <c- o><c- o>^=</c-></c->  <c- o><c- o>|=</c-></c-></code>
</pre>
     <li> In simple assignment (<code class="highlight"><c- o>=</c-></code>), the object referred to by the left operand is
  modified by replacing its value with the result of the right operand. 
     <li>
       If the left operand is not of class type
      <ins> and is not <code class="highlight"><c- k>volatile</c-></code></ins>
      , the
  expression is implicitly converted to the cv-unqualified type of the left
  operand. 
     <li>
      <ins>If the left operand is not of class type and is <code class="highlight"><c- k>volatile</c-></code>, the
  expression is implicitly converted to the cv-unqualified type of the left
  operand (this usage is deprecated; see [<strong>depr.volatile</strong>]).</ins>
     <li> If the left operand is of class type, the class shall be complete. Assignment
  to objects of a class is defined by the copy/move assignment. 
     <li> [ <em>Note:</em> For class objects, assignment is not in general the same as
  initialization. —<em>end note</em> ] 
     <li> When the left operand of an assignment operator is a bit-field that cannot
  represent the value of the expression, the resulting value of the bit-field is
  implementation-defined. 
     <li>
      <ins>Expressions of the form <code class="highlight"><c- n>E1</c-> <em><c- n>op</c-></em><c- o>=</c-> <c- n>E2</c-></code> where <code class="highlight"><c- n>E1</c-></code> is a <code class="highlight"><c- k>volatile</c-></code>-qualified arithmetic or pointer type shall either be a
  discarded-value expression or appear in an unevaluated context (other usages
  are deprecated; see [<strong>depr.volatile</strong>]).</ins>
     <li>
      <del>The</del>
      <ins>Otherwise, the</ins>
       behavior of an expression of the form <code class="highlight"><c- n>E1</c-> <em><c- n>op</c-></em><c- o>=</c-> <c- n>E2</c-></code> is equivalent to <code class="highlight"><c- n>E1</c-> <c- o>=</c-> <c- n>E1</c-> <em><c- n>op</c-></em> <c- n>E2</c-></code> except that <code class="highlight"><c- n>E1</c-></code> is evaluated only once. In <code class="highlight"><c- o>+=</c-></code> and <code class="highlight"><c- o>-=</c-></code>, <code class="highlight"><c- n>E1</c-></code> shall either
  have arithmetic type or be a pointer to a possibly cv-qualified
  completely-defined object type. In all other cases, <code class="highlight"><c- n>E1</c-></code> shall have arithmetic
  type. 
     <li> If the value being stored in an object is read via another object that
  overlaps in any way the storage of the first object, then the overlap shall be
  exact and the two objects shall have the same type, otherwise the behavior is
  undefined. [ <em>Note:</em> This restriction applies to the relationship between the
  left and right sides of the assignment operation; it is not a statement about
  how the target of the assignment may be aliased in general.
  See [<strong>basic.lval</strong>]. —<em>end note</em> ] 
     <li>
       A <em>braced-init-list</em> may appear on the right-hand side of 
      <ol>
       <li>an assignment to a scalar, in which case the initializer list shall have at most a single element. The meaning of <code class="highlight"><c- n>x</c-> <c- o>=</c-> <c- p>{</c-><c- n>v</c-><c- p>}</c-></code>, where <code class="highlight"><c- n>T</c-></code> is the scalar type of the expression <code class="highlight"><c- n>x</c-></code>, is that of <code class="highlight"><c- n>x</c-> <c- o>=</c-> <c- n>T</c-><c- p>{</c-><c- n>v</c-><c- p>}</c-></code>. The meaning of <code class="highlight"><c- n>x</c-> <c- o>=</c-> <c- p>{}</c-></code> is <code class="highlight"><c- n>x</c-> <c- o>=</c-> <c- n>T</c-><c- p>{}</c-></code>. 
       <li>an assignment to an object of class type, in which case the initializer list is passed as the argument to the assignment operator function selected by overload resolution. 
      </ol>
    </ol>
   </blockquote>
   <h3 class="heading settled" data-level="3.8" id="dcl.type.cv"><span class="secno">3.8. </span><span class="content">The cv-qualifiers [<strong>dcl.type.cv</strong>]</span><a class="self-link" href="#dcl.type.cv"></a></h3>
   <p>No changes.</p>
   <blockquote>
    <p>The semantics of an access through a <code class="highlight"><c- k>volatile</c-></code> glvalue are
  implementation-defined. If an attempt is made to access an object defined with
  a <code class="highlight"><c- k>volatile</c-></code>-qualified type through the use of a non-<code class="highlight"><c- k>volatile</c-></code> glvalue, the
  behavior is undefined.</p>
    <p>[ <em>Note:</em> <code class="highlight"><c- k>volatile</c-></code> is a hint to the implementation to avoid aggressive
  optimization involving the object because the value of the object might be
  changed by means undetectable by an implementation. Furthermore, for some
  implementations, <code class="highlight"><c- k>volatile</c-></code> might indicate that special hardware instructions
  are required to access the object. See [<strong>intro.execution</strong>] for detailed
  semantics. In general, the semantics of <code class="highlight"><c- k>volatile</c-></code> are intended to be the same
  in C++ as they are in C. —<em>end note</em> ]</p>
   </blockquote>
   <h3 class="heading settled" data-level="3.9" id="dcl.fct"><span class="secno">3.9. </span><span class="content">Functions [<strong>dcl.fct</strong>]</span><a class="self-link" href="#dcl.fct"></a></h3>
   <p>Modify as follows.</p>
   <blockquote>
    <p>
     The <em>parameter-declaration-clause</em> determines the arguments that can be
  specified, and their processing, when the function is called. [ <em>Note:</em> The <em>parameter-declaration-clause</em> is used to convert the arguments specified on
  the function call; see [<strong>expr.call</strong>] —<em>end note</em> ] If the <em>parameter-declaration-clause</em> is empty, the function takes no arguments. A
  parameter list consisting of a single unnamed parameter of non-dependent type <code class="highlight"><c- b>void</c-></code> is equivalent to an empty parameter list. Except for this special case,
  a parameter shall not have type <em>cv</em> <code class="highlight"><c- b>void</c-></code>. 
     <ins>A parameter can have a <code class="highlight"><c- k>volatile</c-></code>-qualified type (this usage is deprecated; see [<strong>depr.volatile</strong>]).</ins>
      If the <em>parameter-declaration-clause</em> terminates with an ellipsis or a
  function parameter pack, the number of arguments shall be equal to or greater
  than the number of parameters that do not have a default argument and are not
  function parameter packs. Where syntactically correct and where "<code class="highlight"><c- p>...</c-></code>" is not
  part of an <em>abstract-declarator</em>, "<code class="highlight"><c- p>,</c-> <c- p>...</c-></code>" is synonymous with "<code class="highlight"><c- p>...</c-></code>".
    </p>
    <p>[...]</p>
    <p>The type of a function is determined using the following rules. The type of
  each parameter (including function parameter packs) is determined from its own <em>decl-specifier-seq</em> and <em>declarator</em>. After determining the type of each
  parameter, any parameter of type "array of <code class="highlight"><c- n>T</c-></code>" or of function type <code class="highlight"><c- n>T</c-></code> is
  adjusted to be "pointer to <code class="highlight"><c- n>T</c-></code>". After producing the list of parameter types,
  any top-level <em>cv-qualifier</em>s modifying a parameter type are deleted when
  forming the function type. The resulting list of transformed parameter types
  and the presence or absence of the ellipsis or a function parameter pack is
  the function’s <em>parameter-type-list</em>.</p>
    <p>[...]</p>
    <p>Functions shall not have a return type of type array or function, although
  they may have a return type of type pointer or reference to such things. There
  shall be no arrays of functions, although there can be arrays of pointers to
  functions.</p>
    <ins>Functions can have a <code class="highlight"><c- k>volatile</c-></code> qualified return type (this usage is
  deprecated; see [<strong>depr.volatile</strong>]).</ins>
   </blockquote>
   <h3 class="heading settled" data-level="3.10" id="class.mfct.non-static"><span class="secno">3.10. </span><span class="content">Non-static member functions [<strong>class.mfct.non-static</strong>]</span><a class="self-link" href="#class.mfct.non-static"></a></h3>
   <p>No changes.</p>
   <blockquote>
    <p>A non-static member function may be declared <code class="highlight"><c- k>const</c-></code>, <code class="highlight"><c- k>volatile</c-></code>, or <code class="highlight"><c- k>const</c-> <c- k>volatile</c-></code>. These cv-qualifiers affect the type of the <code class="highlight"><c- k>this</c-></code> pointer.
  They also affect the function type of the member function; a member
  function declared <code class="highlight"><c- k>const</c-></code> is a <code class="highlight"><c- k>const</c-></code> member function, a member function declared <code class="highlight"><c- k>volatile</c-></code> is a <code class="highlight"><c- k>volatile</c-></code> member function and a member function declared <code class="highlight"><c- k>const</c-> <c- k>volatile</c-></code> is a <code class="highlight"><c- k>const</c-> <c- k>volatile</c-></code> member function.</p>
   </blockquote>
   <h3 class="heading settled" data-level="3.11" id="class.this"><span class="secno">3.11. </span><span class="content">The this pointer [<strong>class.this</strong>]</span><a class="self-link" href="#class.this"></a></h3>
   <p>No changes.</p>
   <blockquote>
    <p>In the body of a non-static member function, the keyword <code class="highlight"><c- k>this</c-></code> is a prvalue
   expression whose value is the address of the object for which the function is
   called. The type of <code class="highlight"><c- k>this</c-></code> in a member function of a class <code class="highlight"><c- n>X</c-></code> is <code class="highlight"><c- n>X</c-><c- o>*</c-></code>. If
   the member function is declared <code class="highlight"><c- k>const</c-></code>, the type of <code class="highlight"><c- k>this</c-></code> is <code class="highlight"><c- k>const</c-> <c- n>X</c-><c- o>*</c-></code>, if
   the member function is declared <code class="highlight"><c- k>volatile</c-></code>, the type of <code class="highlight"><c- k>this</c-></code> is <code class="highlight"><c- k>volatile</c-> <c- n>X</c-><c- o>*</c-></code>, and if the member function is declared <code class="highlight"><c- k>const</c-> <c- k>volatile</c-></code>, the type of <code class="highlight"><c- k>this</c-></code> is <code class="highlight"><c- k>const</c-> <c- k>volatile</c-> <c- n>X</c-><c- o>*</c-></code>.</p>
    <p><code class="highlight"><c- k>volatile</c-></code> semantics apply in <code class="highlight"><c- k>volatile</c-></code> member functions when accessing the
   object and its non-static data members.</p>
   </blockquote>
   <h3 class="heading settled" data-level="3.12" id="class.ctor"><span class="secno">3.12. </span><span class="content">Constructors [<strong>class.ctor</strong>]</span><a class="self-link" href="#class.ctor"></a></h3>
   <p>No changes.</p>
   <blockquote>
    <p>A constructor can be invoked for a <code class="highlight"><c- k>const</c-></code>, <code class="highlight"><c- k>volatile</c-></code> or <code class="highlight"><c- k>const</c-> <c- k>volatile</c-></code> object. <code class="highlight"><c- k>const</c-></code> and <code class="highlight"><c- k>volatile</c-></code> semantics are not applied on an object under
  construction. They come into effect when the constructor for the most derived
  object ends.</p>
   </blockquote>
   <h3 class="heading settled" data-level="3.13" id="class.dtor"><span class="secno">3.13. </span><span class="content">Destructors [<strong>class.dtor</strong>]</span><a class="self-link" href="#class.dtor"></a></h3>
   <p>No changes.</p>
   <blockquote>
    <p>A destructor is used to destroy objects of its class type. The address of a
  destructor shall not be taken. A destructor can be invoked for a <code class="highlight"><c- k>const</c-></code>, <code class="highlight"><c- k>volatile</c-></code> or <code class="highlight"><c- k>const</c-> <c- k>volatile</c-></code> object. <code class="highlight"><c- k>const</c-></code> and <code class="highlight"><c- k>volatile</c-></code> semantics are
  not applied on an object under destruction. They stop being in effect when the
  destructor for the most derived object starts.</p>
   </blockquote>
   <h3 class="heading settled" data-level="3.14" id="over.load"><span class="secno">3.14. </span><span class="content">Overloadable declarations [<strong>over.load</strong>]</span><a class="self-link" href="#over.load"></a></h3>
   <p>Modify as follows.</p>
   <blockquote>
    <p>
     Parameter declarations that differ only in the presence or absence of <code class="highlight"><c- k>const</c-></code> 
     <del>and/or <code class="highlight"><c- k>volatile</c-></code></del>
      are equivalent. That is, the <code class="highlight"><c- k>const</c-></code> 
     <del>and <code class="highlight"><c- k>volatile</c-></code> type-specifiers</del>
     <ins>type-specifier</ins>
      for each parameter type 
     <del>are</del>
     <ins>is</ins>
      ignored when determining which function is being declared, defined, or called.
    </p>
    <ins>Parameter declarations that differ only in the presence or absence of <code class="highlight"><c- k>volatile</c-></code> are equivalent (this usage is deprecated; see
  [<strong>depr.volatile</strong>]).</ins>
   </blockquote>
   <h3 class="heading settled" data-level="3.15" id="over.built"><span class="secno">3.15. </span><span class="content">Built-in operators [<strong>over.built</strong>]</span><a class="self-link" href="#over.built"></a></h3>
   <p>Modify as follows.</p>
   <blockquote>
    <p>
     In the remainder of this section, <em>vq</em> represents either <code class="highlight"><c- k>volatile</c-></code> or no
  cv-qualifier
     <ins> (usage of <em>vq</em> representing <code class="highlight"><c- k>volatile</c-></code> is deprecated; see
  [<strong>depr.volatile</strong>])</ins>
     .
    </p>
    <p>For every pair (<em>T</em>, <em>vq</em>), where <em>T</em> is an arithmetic type other than <code class="highlight"><c- b>bool</c-></code>,
  there exist candidate operator functions of the form</p>
<pre class="highlight"><code class="highlight"><c- n><c- n>vq</c-></c-> <c- n><c- n>T</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>vq</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- k><c- k>operator</c-></c-><c- o><c- o>++</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>vq</c-></c-> <c- n><c- n>T</c-></c-> <c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- b><c- b>int</c-></c-><c- p><c- p>);</c-></c->
</code></pre>
    <p>For every pair (<em>T</em>, <em>vq</em>), where <em>T</em> is an arithmetic type other than <code class="highlight"><c- b>bool</c-></code>,
  there exist candidate operator functions of the form</p>
<pre class="highlight"><code class="highlight"><c- n><c- n>vq</c-></c-> <c- n><c- n>T</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>vq</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- k><c- k>operator</c-></c-><c- o><c- o>--</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>vq</c-></c-> <c- n><c- n>T</c-></c-> <c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- b><c- b>int</c-></c-><c- p><c- p>);</c-></c->
</code></pre>
    <p>For every pair (<em>T</em>, <em>vq</em>), where <em>T</em> is a cv-qualified or cv-unqualified
  object type, there exist candidate operator functions of the form</p>
<pre class="highlight"><code class="highlight"><c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- n><c- n>vq</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>T</c-></c-><c- o><c- o>*</c-></c-><c- n><c- n>vq</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- n><c- n>vq</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>T</c-></c-><c- o><c- o>*</c-></c-><c- n><c- n>vq</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- 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- n><c- n>vq</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- b><c- b>int</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- n><c- n>vq</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- b><c- b>int</c-></c-><c- p><c- p>);</c-></c->
</code></pre>
    <p>For every quintuple (<em>C1</em>, <em>C2</em>, <em>T</em>, <em>cv1</em>, <em>cv2</em>), where <em>C2</em> is a class
  type, <em>C1</em> is the same type as <em>C2</em> or is a derived class of <em>C2</em>, and <em>T</em> is an
  object type or a function type, there exist candidate operator functions of
  the form</p>
<pre class="highlight"><code class="highlight"><em><c- n><c- n>cv12</c-></c-></em> <c- n><c- n>T</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-><em><c- n><c- n>cv1</c-></c-></em> <c- n><c- n>C1</c-></c-><c- o><c- o>*</c-></c-><c- p><c- p>,</c-></c-> <em><c- n><c- n>cv2</c-></c-></em> <c- n><c- n>T</c-></c-> <c- n><c- n>C2</c-></c-><c- o><c- o>::*</c-></c-><c- p><c- p>);</c-></c->
</code></pre>
    <p>For every triple (<em>L</em>, <em>vq</em>, <em>R</em>), where <em>L</em> is an arithmetic type, and <em>R</em> is
  a promoted arithmetic type, there exist candidate operator functions of the
  form</p>
<pre class="highlight"><code class="highlight"><c- n><c- n>vq</c-></c-> <c- n><c- n>L</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>vq</c-></c-> <c- n><c- n>L</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>R</c-></c-><c- p><c- p>);</c-></c->
<c- n><c- n>vq</c-></c-> <c- n><c- n>L</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>vq</c-></c-> <c- n><c- n>L</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>R</c-></c-><c- p><c- p>);</c-></c->
<c- n><c- n>vq</c-></c-> <c- n><c- n>L</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>vq</c-></c-> <c- n><c- n>L</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>R</c-></c-><c- p><c- p>);</c-></c->
<c- n><c- n>vq</c-></c-> <c- n><c- n>L</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>vq</c-></c-> <c- n><c- n>L</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>R</c-></c-><c- p><c- p>);</c-></c->
<c- n><c- n>vq</c-></c-> <c- n><c- n>L</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>vq</c-></c-> <c- n><c- n>L</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>R</c-></c-><c- p><c- p>);</c-></c->
</code></pre>
    <p>For every pair (<em>T</em>, <em>vq</em>), where <em>T</em> is any type, there exist candidate
  operator functions of the form</p>
<pre class="highlight"><code class="highlight"><c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- n><c- n>vq</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>T</c-></c-><c- o><c- o>*</c-></c-><c- n><c- n>vq</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->
</code></pre>
    <p>For every pair (<em>T</em>, <em>vq</em>), where <em>T</em> is an enumeration or pointer to member
  type, there exist candidate operator functions of the form</p>
<pre class="highlight"><code class="highlight"><c- n><c- n>vq</c-></c-> <c- n><c- n>T</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>vq</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->
</code></pre>
    <p>For every pair (<em>T</em>, <em>vq</em>), where <em>T</em> is a cv-qualified or cv-unqualified
  object type, there exist candidate operator functions of the form</p>
<pre class="highlight"><code class="highlight"><c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-><c- n><c- n>vq</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>T</c-></c-><c- o><c- o>*</c-></c-><c- n><c- n>vq</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>std</c-></c-><c- o><c- o>::</c-></c-><c- b><c- b>ptrdiff_t</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>vq</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>T</c-></c-><c- o><c- o>*</c-></c-><c- n><c- n>vq</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>std</c-></c-><c- o><c- o>::</c-></c-><c- b><c- b>ptrdiff_t</c-></c-><c- p><c- p>);</c-></c->
</code></pre>
    <p>For every triple (<em>L</em>, <em>vq</em>, <em>R</em>), where <em>L</em> is an integral type, and <em>R</em> is a
  promoted integral type, there exist candidate operator functions of the form</p>
<pre class="highlight"><code class="highlight"><c- n><c- n>vq</c-></c-> <c- n><c- n>L</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>vq</c-></c-> <c- n><c- n>L</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>R</c-></c-><c- p><c- p>);</c-></c->
<c- n><c- n>vq</c-></c-> <c- n><c- n>L</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>&lt;&lt;=</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>vq</c-></c-> <c- n><c- n>L</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>R</c-></c-><c- p><c- p>);</c-></c->
<c- n><c- n>vq</c-></c-> <c- n><c- n>L</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>vq</c-></c-> <c- n><c- n>L</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>R</c-></c-><c- p><c- p>);</c-></c->
<c- n><c- n>vq</c-></c-> <c- n><c- n>L</c-></c-><c- o><c- o>&amp;</c-></c-> <c- k><c- k>operator</c-></c-><c- o><c- o>&amp;=</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>vq</c-></c-> <c- n><c- n>L</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>R</c-></c-><c- p><c- p>);</c-></c->
<c- n><c- n>vq</c-></c-> <c- n><c- n>L</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>vq</c-></c-> <c- n><c- n>L</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>R</c-></c-><c- p><c- p>);</c-></c->
<c- n><c- n>vq</c-></c-> <c- n><c- n>L</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>vq</c-></c-> <c- n><c- n>L</c-></c-><c- o><c- o>&amp;</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>R</c-></c-><c- p><c- p>);</c-></c->
</code></pre>
   </blockquote>
   <h3 class="heading settled" data-level="3.16" id="tuple"><span class="secno">3.16. </span><span class="content">Tuples [<strong>tuple</strong>]</span><a class="self-link" href="#tuple"></a></h3>
   <p>Modify as follows.</p>
   <blockquote>
    <p>Header <code class="highlight"><c- o>&lt;</c-><c- n>tuple</c-><c- o>></c-></code> synopsis [<strong>tuple.syn</strong>]:</p>
<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- p><c- p>[...]</c-></c->
    
<c- c1><c- c1>// [</c-></c-><i><c- c1><c- c1>tuple.helper</c-></c-></i><c- c1><c- c1>, tuple helper classes</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>class</c-></c-> <c- nc><c- nc>tuple_size</c-></c-><c- p><c- p>;</c-></c->                  <c- c1><c- c1>// not defined</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>class</c-></c-> <c- nc><c- nc>tuple_size</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c->
<del><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>class</c-></c-> <c- nc><c- nc>tuple_size</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c-></del>
<del><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>class</c-></c-> <c- nc><c- nc>tuple_size</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c-></del>
    
<c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>class</c-></c-><c- p><c- p>...</c-></c-> <c- n><c- n>Types</c-></c-><c- o><c- o>></c-></c-> <c- k><c- k>class</c-></c-> <c- nc><c- nc>tuple_size</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>tuple</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>Types</c-></c-><c- p><c- p>...</c-></c-><c- o><c- o>>></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>size_t</c-></c-> <c- n><c- n>I</c-></c-><c- p><c- p>,</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>class</c-></c-> <c- nc><c- nc>tuple_element</c-></c-><c- p><c- p>;</c-></c->     <c- c1><c- c1>// not defined</c-></c->
<c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- b><c- b>size_t</c-></c-> <c- n><c- n>I</c-></c-><c- p><c- p>,</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>class</c-></c-> <c- nc><c- nc>tuple_element</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>I</c-></c-><c- p><c- p>,</c-></c-> <c- k><c- k>const</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c->
<del><c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- b><c- b>size_t</c-></c-> <c- n><c- n>I</c-></c-><c- p><c- p>,</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>class</c-></c-> <c- nc><c- nc>tuple_element</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>I</c-></c-><c- p><c- p>,</c-></c-> <c- k><c- k>volatile</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c-></del>
<del><c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- b><c- b>size_t</c-></c-> <c- n><c- n>I</c-></c-><c- p><c- p>,</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>class</c-></c-> <c- nc><c- nc>tuple_element</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>I</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>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c-></del>

<c- p><c- p>[...]</c-></c->
    
<c- p><c- p>}</c-></c->
    
</code></pre>
    <p>[...]</p>
    <p>Tuple helper classes [<strong>tuple.helper</strong>]</p>
<pre class="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-> <c- k><c- k>class</c-></c-> <c- nc><c- nc>tuple_size</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c->
 <del><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>class</c-></c-> <c- nc><c- nc>tuple_size</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c->
</del> <del><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>class</c-></c-> <c- nc><c- nc>tuple_size</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c->
</del></code></pre>
    <p>Let <code class="highlight"><c- n>TS</c-></code> denote <code class="highlight"><c- n>tuple_size</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> of the <em>cv</em>-unqualified type <code class="highlight"><c- n>T</c-></code>. If the
  expression <code class="highlight"><c- n>TS</c-><c- o>::</c-><c- n>value</c-></code> is well-formed when treated as an unevaluated operand,
  then each of the three templates shall satisfy the <code class="highlight"><c- n>TransformationTrait</c-></code> requirements with a base characteristic of</p>
<pre class="highlight"><code class="highlight"><c- n><c- n>integral_constant</c-></c-><c- o><c- o>&lt;</c-></c-><c- b><c- b>size_t</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>TS</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>value</c-></c-><c- o><c- o>></c-></c-></code></pre>
    <p>Otherwise, they shall have no member <code class="highlight"><c- n>value</c-></code>.</p>
    <p>Access checking is performed as if in a context unrelated to <code class="highlight"><c- n>TS</c-></code> and <code class="highlight"><c- n>T</c-></code>.
  Only the validity of the immediate context of the expression is considered. [ <em>Note:</em> The compilation of the expression can result in side effects such as
  the instantiation of class template specializations and function template
  specializations, the generation of implicitly-defined functions, and so on.
  Such side effects are not in the "immediate context" and can result in the
  program being ill-formed. —<em>end note</em> ]</p>
    <p>
     In addition to being available via inclusion of the <code class="highlight"><c- o>&lt;</c-><c- n>tuple</c-><c- o>></c-></code> header,
  the 
     <del>three templates are</del>
     <ins>template is</ins>
      available when any of the
  headers <code class="highlight"><c- o>&lt;</c-><c- n>array</c-><c- o>></c-></code>, <code class="highlight"><c- o>&lt;</c-><c- n>ranges</c-><c- o>></c-></code>, or <code class="highlight"><c- o>&lt;</c-><c- n>utility</c-><c- o>></c-></code> are included.
    </p>
<pre class="highlight"><code class="highlight">  
<c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- b><c- b>size_t</c-></c-> <c- n><c- n>I</c-></c-><c- p><c- p>,</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>class</c-></c-> <c- nc><c- nc>tuple_element</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>I</c-></c-><c- p><c- p>,</c-></c-> <c- k><c- k>const</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c->
<del><c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- b><c- b>size_t</c-></c-> <c- n><c- n>I</c-></c-><c- p><c- p>,</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>class</c-></c-> <c- nc><c- nc>tuple_element</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>I</c-></c-><c- p><c- p>,</c-></c-> <c- k><c- k>volatile</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c-></del>
<del><c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- b><c- b>size_t</c-></c-> <c- n><c- n>I</c-></c-><c- p><c- p>,</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>class</c-></c-> <c- nc><c- nc>tuple_element</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>I</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>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c-></del>
</code></pre>
    <p>
     Let <code class="highlight"><c- n>TE</c-></code> denote <code class="highlight"><c- n>tuple_element_t</c-><c- o>&lt;</c-><c- n>I</c-><c- p>,</c-> <c- n>T</c-><c- o>></c-></code> of the <em>cv</em>-unqualified type <code class="highlight"><c- n>T</c-></code>.
  Then 
     <del>each of the three templates</del>
     <ins>the template</ins>
      shall satisfy
  the <code class="highlight"><c- n>TransformationTrait</c-></code> requirements with a member typedef <code class="highlight"><c- n>type</c-></code> that names
  the following type:
     <ins> <code class="highlight"><c- n>add_const_t</c-><c- o>&lt;</c-><c- n>TE</c-><c- o>></c-></code>.</ins>
    </p>
    <del>
     <ul>
      <li>for the first specialization, <code class="highlight"><c- n>add_const_t</c-><c- o>&lt;</c-><c- n>TE</c-><c- o>></c-></code>, 
      <li>for the second specialization, <code class="highlight"><c- n>add_volatile_t</c-><c- o>&lt;</c-><c- n>TE</c-><c- o>></c-></code>, and 
      <li>for the third specialization, <code class="highlight"><c- n>add_cv_t</c-><c- o>&lt;</c-><c- n>TE</c-><c- o>></c-></code>. 
     </ul>
    </del>
    <p>
     In addition to being available via inclusion of the <code class="highlight"><c- o>&lt;</c-><c- n>tuple</c-><c- o>></c-></code> header,
  the 
     <del>three templates are</del>
     <ins>template is</ins>
      available when any of the
  headers <code class="highlight"><c- o>&lt;</c-><c- n>array</c-><c- o>></c-></code>, <code class="highlight"><c- o>&lt;</c-><c- n>ranges</c-><c- o>></c-></code>, or <code class="highlight"><c- o>&lt;</c-><c- n>utility</c-><c- o>></c-></code> are included.
    </p>
   </blockquote>
   <h3 class="heading settled" data-level="3.17" id="variant"><span class="secno">3.17. </span><span class="content">Variants [<strong>variant</strong>]</span><a class="self-link" href="#variant"></a></h3>
   <p>Modify as follows.</p>
   <blockquote>
    <p><code class="highlight"><c- o>&lt;</c-><c- n>variant</c-><c- o>></c-></code> synopsis [<strong>variant.syn</strong>]</p>
<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- c1><c- c1>// [</c-></c-><i><c- c1><c- c1>variant.variant</c-></c-></i><c- c1><c- c1>], class template variant</c-></c->
<c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>class</c-></c-><c- p><c- p>...</c-></c-> <c- n><c- n>Types</c-></c-><c- o><c- o>></c-></c->
  <c- k><c- k>class</c-></c-> <c- nc><c- nc>variant</c-></c-><c- p><c- p>;</c-></c->

<c- c1><c- c1>// [</c-></c-><i><c- c1><c- c1>variant.helper</c-></c-></i><c- c1><c- c1>], variant helper classes</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>variant_size</c-></c-><c- p><c- p>;</c-></c->                   <c- c1><c- c1>// not defined</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>variant_size</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>const</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c->
<del><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>variant_size</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>volatile</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c-></del>
<del><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>variant_size</c-></c-><c- o><c- o>&lt;</c-></c-><c- k><c- k>const</c-></c-> <c- k><c- k>volatile</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c-></del>
<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- kr><c- kr>inline</c-></c-> <c- k><c- k>constexpr</c-></c-> <c- b><c- b>size_t</c-></c-> <c- n><c- n>variant_size_v</c-></c-> <c- o><c- o>=</c-></c-> <c- n><c- n>variant_size</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</c-></c-><c- p><c- p>;</c-></c->

<c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>class</c-></c-><c- p><c- p>...</c-></c-> <c- n><c- n>Types</c-></c-><c- o><c- o>></c-></c->
  <c- k><c- k>struct</c-></c-> <c- n><c- n>variant_size</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>variant</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>Types</c-></c-><c- p><c- p>...</c-></c-><c- o><c- o>>></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>size_t</c-></c-> <c- n><c- n>I</c-></c-><c- p><c- p>,</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>variant_alternative</c-></c-><c- p><c- p>;</c-></c->  <c- c1><c- c1>// not defined</c-></c->
<c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- b><c- b>size_t</c-></c-> <c- n><c- n>I</c-></c-><c- p><c- p>,</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>variant_alternative</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>I</c-></c-><c- p><c- p>,</c-></c-> <c- k><c- k>const</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c->
<del><c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- b><c- b>size_t</c-></c-> <c- n><c- n>I</c-></c-><c- p><c- p>,</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>variant_alternative</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>I</c-></c-><c- p><c- p>,</c-></c-> <c- k><c- k>volatile</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c-></del>
<del><c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- b><c- b>size_t</c-></c-> <c- n><c- n>I</c-></c-><c- p><c- p>,</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>variant_alternative</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>I</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>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c-></del>

<c- p><c- p>[...]</c-></c->
  
<c- p><c- p>}</c-></c->
  
</code></pre>
    <p><code class="highlight"><c- n>variant</c-></code> helper classes [<strong>variant.helper</strong>]</p>
<pre class="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-> <c- k><c- k>struct</c-></c-> <c- n><c- n>variant_size</c-></c-><c- p><c- p>;</c-></c-></code></pre>
    <p><em>Remark:</em> All specializations of <code class="highlight"><c- n>variant_size</c-></code> shall satisfy the <code class="highlight"><c- n>UnaryTypeTrait</c-></code> requirements with a base characteristic of <code class="highlight"><c- n>integral_constant</c-><c- o>&lt;</c-><c- b>size_t</c-><c- p>,</c-> <c- n>N</c-><c- o>></c-></code> for some <code class="highlight"><c- n>N</c-></code>.</p>
<pre class="highlight"><c- k>template</c-><c- o>&lt;</c-><c- k>class</c-> <c- nc>T</c-><c- o>></c-> <c- k>class</c-> <c- nc>variant_size</c-><c- o>&lt;</c-><c- k>const</c-> <c- n>T</c-><c- o>></c-><c- p>;</c->
<del><c- k>template</c-><c- o>&lt;</c-><c- k>class</c-> <c- nc>T</c-><c- o>></c-> <c- k>class</c-> <c- nc>variant_size</c-><c- o>&lt;</c-><c- k>volatile</c-> <c- n>T</c-><c- o>></c-><c- p>;</c-></del>
<del><c- k>template</c-><c- o>&lt;</c-><c- k>class</c-> <c- nc>T</c-><c- o>></c-> <c- k>class</c-> <c- nc>variant_size</c-><c- o>&lt;</c-><c- k>const</c-> <c- k>volatile</c-> <c- n>T</c-><c- o>></c-><c- p>;</c-></del>
</pre>
    <p>
     Let <code class="highlight"><c- n>VS</c-></code> denote <code class="highlight"><c- n>variant_size</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> of the <em>cv</em>-unqualified type <code class="highlight"><c- n>T</c-></code>. Then 
     <del>each
  of the three templates</del>
     <ins>the template</ins>
      shall satisfy the <code class="highlight"><c- n>UnaryTypeTrait</c-></code> requirements with a
  base characteristic of <code class="highlight"><c- n>integral_constant</c-><c- o>&lt;</c-><c- b>size_t</c-><c- p>,</c-> <c- n>VS</c-><c- o>::</c-><c- n>value</c-><c- o>></c-></code>.
    </p>
<pre class="highlight"><code class="highlight"><c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>class</c-></c-><c- p><c- p>...</c-></c-> <c- n><c- n>Types</c-></c-><c- o><c- o>></c-></c->
  <c- k><c- k>struct</c-></c-> <c- n><c- n>variant_size</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>variant</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>Types</c-></c-><c- p><c- p>...</c-></c-><c- o><c- o>>></c-></c-> <c- o><c- o>:</c-></c-> <c- n><c- n>integral_constant</c-></c-><c- o><c- o>&lt;</c-></c-><c- b><c- b>size_t</c-></c-><c- p><c- p>,</c-></c-> <c- k><c- k>sizeof</c-></c-><c- p><c- p>...(</c-></c-><c- n><c- n>Types</c-></c-><c- p><c- p>)</c-></c-><c- o><c- o>></c-></c-> <c- p><c- p>{</c-></c-> <c- p><c- p>};</c-></c->
</code></pre>
<pre class="highlight"><code class="highlight"><c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- b><c- b>size_t</c-></c-> <c- n><c- n>I</c-></c-><c- p><c- p>,</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>class</c-></c-> <c- nc><c- nc>variant_alternative</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>I</c-></c-><c- p><c- p>,</c-></c-> <c- k><c- k>const</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c->
<del><c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- b><c- b>size_t</c-></c-> <c- n><c- n>I</c-></c-><c- p><c- p>,</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>class</c-></c-> <c- nc><c- nc>variant_alternative</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>I</c-></c-><c- p><c- p>,</c-></c-> <c- k><c- k>volatile</c-></c-> <c- n><c- n>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c-></del>
<del><c- k><c- k>template</c-></c-><c- o><c- o>&lt;</c-></c-><c- b><c- b>size_t</c-></c-> <c- n><c- n>I</c-></c-><c- p><c- p>,</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>class</c-></c-> <c- nc><c- nc>variant_alternative</c-></c-><c- o><c- o>&lt;</c-></c-><c- n><c- n>I</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>T</c-></c-><c- o><c- o>></c-></c-><c- p><c- p>;</c-></c-></del>
</code></pre>
    <p>
     Let <code class="highlight"><c- n>VA</c-></code> denote <code class="highlight"><c- n>variant_alternative</c-><c- o>&lt;</c-><c- n>I</c-><c- p>,</c-> <c- n>T</c-><c- o>></c-></code> of the <em>cv</em>-unqualified type <code class="highlight"><c- n>T</c-></code>.
  Then 
     <del>each of the three templates</del>
     <ins>the template</ins>
      shall meet the <code class="highlight"><c- n>TransformationTrait</c-></code> requirements with a member typedef <code class="highlight"><c- n>type</c-></code> that names the following type:
     <ins> <code class="highlight"><c- n>add_const_t</c-><c- o>&lt;</c-><c- n>VA</c-><c- o>::</c-><c- n>type</c-><c- o>></c-></code>.</ins>
    </p>
    <del>
     <ul>
      <li>for the first specialization, <code class="highlight"><c- n>add_const_t</c-><c- o>&lt;</c-><c- n>VA</c-><c- o>::</c-><c- n>type</c-><c- o>></c-></code>, 
      <li>for the second specialization, <code class="highlight"><c- n>add_volatile_t</c-><c- o>&lt;</c-><c- n>VA</c-><c- o>::</c-><c- n>type</c-><c- o>></c-></code>, and 
      <li>for the third specialization, <code class="highlight"><c- n>add_cv_t</c-><c- o>&lt;</c-><c- n>VA</c-><c- o>::</c-><c- n>type</c-><c- o>></c-></code>. 
     </ul>
    </del>
   </blockquote>
   <h3 class="heading settled" data-level="3.18" id="atomics"><span class="secno">3.18. </span><span class="content">Atomic operations library [<strong>atomics</strong>]</span><a class="self-link" href="#atomics"></a></h3>
   <p>Modify as follows.</p>
   <blockquote>
    <p>Operations on atomic types [<strong>atomics.types.operations</strong>]</p>
    <p>[ <em>Note:</em> Many operations are volatile-qualified. The "volatile as device
  register" semantics have not changed in the standard. This qualification means
  that volatility is preserved when applying these operations to volatile
  objects. It does not mean that operations on non-volatile objects become
  volatile. —<em>end note</em> ]</p>
    <p>[...]</p>
<pre class="highlight"><code class="highlight"><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->
</code></pre>
    <p><em>Returns:</em> <code class="highlight">true</code> if the object’s operations are lock-free, <code class="highlight">false</code> otherwise.</p>
    <p>[ <em>Note:</em> The return value of the <code class="highlight"><c- n>is_lock_free</c-></code> member function is consistent with the value of <code class="highlight"><c- n>is_always_lock_free</c-></code> for the same type. —<em>end note</em> ]</p>
<pre class="highlight"><code class="highlight"><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- n><c- n>desired</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- n><c- n>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- n><c- n>desired</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- n><c- n>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>
    <p><em>Requires:</em> The <code class="highlight"><c- n>order</c-></code> argument shall not be <code class="highlight"><c- n>memory_order</c-><c- o>::</c-><c- n>consume</c-></code>, <code class="highlight"><c- n>memory_order</c-><c- o>::</c-><c- n>acquire</c-></code>, nor <code class="highlight"><c- n>memory_order</c-><c- o>::</c-><c- n>acq_rel</c-></code>.</p>
    <p><em>Effects:</em> Atomically replaces the value pointed to by <code class="highlight"><c- k>this</c-></code> with the value of <code class="highlight"><c- n>desired</c-></code>. Memory is affected according to the value of <code class="highlight"><c- n>order</c-></code>.</p>
    <ins><em>Constraints:</em> <code class="highlight"><c- n>is_volatile</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> is <code class="highlight">false</code>, or <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>::</c-><c- n>is_always_lock_free</c-></code> is <code class="highlight">true</code>.</ins>
<pre class="highlight"><code class="highlight"><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- n><c- n>desired</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- n><c- n>desired</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
</code></pre>
    <p><em>Effects:</em> Equivalent to <code class="highlight"><c- n>store</c-><c- p>(</c-><c- n>desired</c-><c- p>)</c-></code>.</p>
    <p><em>Returns:</em> <code class="highlight"><c- n>desired</c-></code>.</p>
<pre class="highlight"><code class="highlight"><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- n><c- n>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- n><c- n>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>
    <p><em>Requires:</em> The <code class="highlight"><c- n>order</c-></code> argument shall not be <code class="highlight"><c- n>memory_order</c-><c- o>::</c-><c- n>release</c-></code> nor <code class="highlight"><c- n>memory_order</c-><c- o>::</c-><c- n>acq_rel</c-></code>.</p>
    <p><em>Effects:</em> Memory is affected according to the value of <code class="highlight"><c- n>order</c-></code>.</p>
    <p><em>Returns:</em> Atomically returns the value pointed to by <code class="highlight"><c- k>this</c-></code>.</p>
    <ins><em>Constraints:</em> <code class="highlight"><c- n>is_volatile</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> is <code class="highlight">false</code>, or <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>::</c-><c- n>is_always_lock_free</c-></code> is <code class="highlight">true</code>.</ins>
<pre class="highlight"><code class="highlight"><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->
</code></pre>
    <p><em>Effects:</em> Equivalent to: <code class="highlight"><c- k>return</c-> <c- nf>load</c-><c- p>();</c-></code></p>
<pre class="highlight"><code class="highlight"><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- n><c- n>desired</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- n><c- n>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- n><c- n>desired</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- n><c- n>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>
    <p><em>Effects:</em> Atomically replaces the value pointed to by <code class="highlight"><c- k>this</c-></code> with <code class="highlight"><c- n>desired</c-></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.</p>
    <p><em>Returns:</em> Atomically returns the value pointed to by <code class="highlight"><c- k>this</c-></code> immediately before the effects.</p>
    <ins><em>Constraints:</em> <code class="highlight"><c- n>is_volatile</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> is <code class="highlight">false</code>, or <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>::</c-><c- n>is_always_lock_free</c-></code> is <code class="highlight">true</code>.</ins>
<pre class="highlight"><code class="highlight"><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- n><c- n>expected</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-> <c- n><c- n>desired</c-></c-><c- p><c- p>,</c-></c->
                           <c- n><c- n>memory_order</c-></c-> <c- n><c- n>success</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- n><c- n>failure</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- n><c- n>expected</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-> <c- n><c- n>desired</c-></c-><c- p><c- p>,</c-></c->
                           <c- n><c- n>memory_order</c-></c-> <c- n><c- n>success</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- n><c- n>failure</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- n><c- n>expected</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-> <c- n><c- n>desired</c-></c-><c- p><c- p>,</c-></c->
                             <c- n><c- n>memory_order</c-></c-> <c- n><c- n>success</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- n><c- n>failure</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- n><c- n>expected</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-> <c- n><c- n>desired</c-></c-><c- p><c- p>,</c-></c->
                             <c- n><c- n>memory_order</c-></c-> <c- n><c- n>success</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- n><c- n>failure</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- n><c- n>expected</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-> <c- n><c- n>desired</c-></c-><c- p><c- p>,</c-></c->
                           <c- n><c- n>memory_order</c-></c-> <c- n><c- n>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- n><c- n>expected</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-> <c- n><c- n>desired</c-></c-><c- p><c- p>,</c-></c->
                           <c- n><c- n>memory_order</c-></c-> <c- n><c- n>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- n><c- n>expected</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-> <c- n><c- n>desired</c-></c-><c- p><c- p>,</c-></c->
                             <c- n><c- n>memory_order</c-></c-> <c- n><c- n>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- n><c- n>expected</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>T</c-></c-> <c- n><c- n>desired</c-></c-><c- p><c- p>,</c-></c->
                             <c- n><c- n>memory_order</c-></c-> <c- n><c- n>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>
    <p><em>Requires:</em> The <code class="highlight"><c- n>failure</c-></code> argument shall not be <code class="highlight"><c- n>memory_order</c-><c- o>::</c-><c- n>release</c-></code> nor <code class="highlight"><c- n>memory_order</c-><c- o>::</c-><c- n>acq_rel</c-></code>.</p>
    <p><em>Effects:</em> Retrieves the value in <code class="highlight"><c- n>expected</c-></code>. It then atomically compares the value representation of the value pointed to by <code class="highlight"><c- k>this</c-></code> for equality with that previously retrieved from <code class="highlight"><c- n>expected</c-></code>,eand if true, replaces the value pointed to by <code class="highlight"><c- k>this</c-></code> with that in <code class="highlight"><c- n>desired</c-></code>. If and only if the comparison is true, memory is affected according to the value of <code class="highlight"><c- n>success</c-></code>, and if the comparison is false, memory is affected according to the value of <code class="highlight"><c- n>failure</c-></code>. When only one <code class="highlight"><c- n>memory_order</c-></code> argument is supplied, the value of <code class="highlight"><c- n>success</c-></code> is <code class="highlight"><c- n>order</c-></code>, and the value of <code class="highlight"><c- n>failure</c-></code> is <code class="highlight"><c- n>order</c-></code> except that a value of <code class="highlight"><c- n>memory_order</c-><c- o>::</c-><c- n>acq_rel</c-></code> shall be replaced by the value <code class="highlight"><c- n>memory_order</c-><c- o>::</c-><c- n>acquire</c-></code> and a value of <code class="highlight"><c- n>memory_order</c-><c- o>::</c-><c- n>release</c-></code> shall be replaced by the value <code class="highlight"><c- n>memory_order</c-><c- o>::</c-><c- n>relaxed</c-></code>. If and only if the comparison is false then, after the atomic operation, the value in <code class="highlight"><c- n>expected</c-></code> is replaced by the value pointed to by <code class="highlight"><c- k>this</c-></code> during the atomic comparison. If the operation returns <code class="highlight">true</code>, these operations are atomic read-modify-write operations on the memory pointed to by <code class="highlight"><c- k>this</c-></code>. Otherwise, these operations are atomic load operations on that memory.</p>
    <p><em>Returns:</em> The result of the comparison.</p>
    <ins><em>Constraints:</em> <code class="highlight"><c- n>is_volatile</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> is <code class="highlight">false</code>, or <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>::</c-><c- n>is_always_lock_free</c-></code> is <code class="highlight">true</code>.</ins>
    <p>[...]</p>
    <p>Specializations for integers [<strong>atomics.types.int</strong>]</p>
<pre class="highlight"><code class="highlight"><c- n><c- n>T</c-></c-> <c- nf><c- nf>fetch_</c-></c-><i><c- nf><c- nf>key</c-></c-></i><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-> <c- n><c- n>operand</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- n><c- n>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>fetch_</c-></c-><i><c- nf><c- nf>key</c-></c-></i><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-> <c- n><c- n>operand</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- n><c- n>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>
    <p><em>Effects:</em> Atomically replaces the value pointed to by <code class="highlight"><c- k>this</c-></code> with the result of the computation applied to the value pointed to by <code class="highlight"><c- k>this</c-></code> and the given <code class="highlight"><c- n>operand</c-></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.</p>
    <p><em>Returns:</em> Atomically, the value pointed to by <code class="highlight"><c- k>this</c-></code> immediately before the effects.</p>
    <ins><em>Constraints:</em> <code class="highlight"><c- n>is_volatile</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> is <code class="highlight">false</code>, or <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>::</c-><c- n>is_always_lock_free</c-></code> is <code class="highlight">true</code>.</ins>
    <p><em>Remarks:</em> For signed integer types, the result is as if the object value and parameters were converted to their corresponding unsigned types, the computation performed on those types, and the result converted back to the signed type. [ <em>Note:</em> There are no undefined results arising from the computation.  —<em>end note</em> ]</p>
<pre class="highlight"><code class="highlight"><c- n><c- n>T</c-></c-> <c- k><c- k>operator</c-></c-> <i><c- n><c- n>op</c-></c-></i><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-> <c- n><c- n>operand</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-> <i><c- n><c- n>op</c-></c-></i><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-> <c- n><c- n>operand</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
</code></pre>
    <p><em>Effects:</em> Equivalent to: <code class="highlight"><c- k>return</c-> <c- nf>fetch_</c-><i><c- nf>key</c-></i><c- p>(</c-><c- n>operand</c-><c- p>)</c-> <i><c- n>op</c-></i> <c- n>operand</c-><c- p>;</c-></code></p>
    <ins><em>Constraints:</em> <code class="highlight"><c- n>is_volatile</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> is <code class="highlight">false</code>, or <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>::</c-><c- n>is_always_lock_free</c-></code> is <code class="highlight">true</code>.</ins>
    <p>Specializations for floating-point types [<strong>atomics.types.float</strong>]</p>
    <p>The following operations perform arithmetic addition and subtraction computations. The key, operator, and computation correspondence are identified in [<strong>atomic.arithmetic.computations</strong>].</p>
<pre class="highlight"><code class="highlight"><c- n><c- n>T</c-></c-> <c- n><c- n>A</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>fetch_</c-></c-><i><c- n><c- n>key</c-></c-></i><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-> <c- n><c- n>operand</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- n><c- n>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- n><c- n>T</c-></c-> <c- n><c- n>A</c-></c-><c- o><c- o>::</c-></c-><c- n><c- n>fetch_</c-></c-><i><c- n><c- n>key</c-></c-></i><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-> <c- n><c- n>operand</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- n><c- n>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>
    <p><em>Effects:</em> Atomically replaces the value pointed to by <code class="highlight"><c- k>this</c-></code> with the result of the computation applied to the value pointed to by <code class="highlight"><c- k>this</c-></code> and the given <code class="highlight"><c- n>operand</c-></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.</p>
    <p><em>Returns:</em> Atomically, the value pointed to by <code class="highlight"><c- k>this</c-></code> immediately before the effects.</p>
    <ins><em>Constraints:</em> <code class="highlight"><c- n>is_volatile</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> is <code class="highlight">false</code>, or <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>::</c-><c- n>is_always_lock_free</c-></code> is <code class="highlight">true</code>.</ins>
    <p><em>Remarks:</em> If the result is not a representable value for its type the result is unspecified, but the operations otherwise have no undefined behavior. Atomic arithmetic operations on <code class="highlight"><i><c- n>floating</c-><c- o>-</c-><c- n>point</c-></i></code> should conform to the <code class="highlight"><c- n>std</c-><c- o>::</c-><c- n>numeric_limits</c-><c- o>&lt;</c-><i><c- n>floating</c-><c- o>-</c-><c- n>point</c-></i><c- o>></c-></code> traits associated with the floating-point type. The floating-point environment for atomic arithmetic operations on <code class="highlight"><i><c- n>floating</c-><c- o>-</c-><c- n>point</c-></i></code> may be different than the calling thread’s floating-point environment.</p>
<pre class="highlight"><code class="highlight"><c- n><c- n>T</c-></c-> <c- k><c- k>operator</c-></c-> <i><c- n><c- n>op</c-></c-></i><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-> <c- n><c- n>operand</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-> <i><c- n><c- n>op</c-></c-></i><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- n><c- n>T</c-></c-> <c- n><c- n>operand</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
</code></pre>
    <p><em>Effects:</em> Equivalent to: <code class="highlight"><c- k>return</c-> <c- nf>fetch_</c-><i><c- nf>key</c-></i><c- p>(</c-><c- n>operand</c-><c- p>)</c-> <i><c- n>op</c-></i> <c- n>operand</c-><c- p>;</c-></code></p>
    <p><em>Remarks:</em> If the result is not a representable value for its type the result is unspecified, but the operations otherwise have no undefined behavior. Atomic arithmetic operations on <code class="highlight"><i><c- n>floating</c-><c- o>-</c-><c- n>point</c-></i></code> should conform to the <code class="highlight"><c- n>std</c-><c- o>::</c-><c- n>numeric_limits</c-><c- o>&lt;</c-><i><c- n>floating</c-><c- o>-</c-><c- n>point</c-></i><c- o>></c-></code> traits associated with the floating-point type. The floating-point environment for atomic arithmetic operations on <code class="highlight"><i><c- n>floating</c-><c- o>-</c-><c- n>point</c-></i></code> may be different than the calling thread’s floating-point environment.</p>
    <p>Partial specialization for pointers [<strong>atomics.types.pointer</strong>]</p>
<pre class="highlight"><code class="highlight"><c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- nf><c- nf>fetch_</c-></c-><i><c- nf><c- nf>key</c-></c-></i><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-> <c- n><c- n>operand</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- n><c- n>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_</c-></c-><i><c- nf><c- nf>key</c-></c-></i><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-> <c- n><c- n>operand</c-></c-><c- p><c- p>,</c-></c-> <c- n><c- n>memory_order</c-></c-> <c- n><c- n>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>
    <p><em>Requires:</em> T shall be an object type, otherwise the program is ill-formed. [ <em>Note:</em> Pointer arithmetic on <code class="highlight"><c- b>void</c-><c- o>*</c-></code> or function pointers is ill-formed. —<em>end note</em> ]</p>
    <p><em>Effects:</em> Atomically replaces the value pointed to by <code class="highlight"><c- k>this</c-></code> with the result of the computation applied to the value pointed to by <code class="highlight"><c- k>this</c-></code> and the given <code class="highlight"><c- n>operand</c-></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.</p>
    <p><em>Returns:</em> Atomically, the value pointed to by <code class="highlight"><c- k>this</c-></code> immediately before the effects.</p>
    <ins><em>Constraints:</em> <code class="highlight"><c- n>is_volatile</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> is <code class="highlight">false</code>, or <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>::</c-><c- n>is_always_lock_free</c-></code> is <code class="highlight">true</code>.</ins>
    <p><em>Remarks:</em> The result may be an undefined address, but the operations otherwise have no undefined behavior.</p>
<pre class="highlight"><code class="highlight"><c- n><c- n>T</c-></c-><c- o><c- o>*</c-></c-> <c- k><c- k>operator</c-></c-> <i><c- n><c- n>op</c-></c-></i><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-> <c- n><c- n>operand</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-> <i><c- n><c- n>op</c-></c-></i><c- o><c- o>=</c-></c-><c- p><c- p>(</c-></c-><c- b><c- b>ptrdiff_t</c-></c-> <c- n><c- n>operand</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
</code></pre>
    <p><em>Effects:</em> Equivalent to: <code class="highlight"><c- k>return</c-> <c- nf>fetch_</c-><i><c- nf>key</c-></i><c- p>(</c-><c- n>operand</c-><c- p>)</c-> <i><c- n>op</c-></i> <c- n>operand</c-><c- p>;</c-></code></p>
    <p>Member operators common to integers and pointers to objects [<strong>atomics.types.memop</strong>]</p>
<pre class="highlight"><code class="highlight"><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- 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- 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->
</code></pre>
    <p><em>Effects:</em> Equivalent to: <code class="highlight"><c- k>return</c-> <c- nf>fetch_add</c-><c- p>(</c-><c- mi>1</c-><c- p>);</c-></code></p>
<pre class="highlight"><code class="highlight"><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- 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- 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->
</code></pre>
    <p><em>Effects:</em> Equivalent to: <code class="highlight"><c- k>return</c-> <c- nf>fetch_sub</c-><c- p>(</c-><c- mi>1</c-><c- p>);</c-></code></p>
<pre class="highlight"><code class="highlight"><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- 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- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
</code></pre>
    <p><em>Effects:</em> Equivalent to: <code class="highlight"><c- k>return</c-> <c- nf>fetch_add</c-><c- p>(</c-><c- mi>1</c-><c- p>)</c-> <c- o>+</c-> <c- mi>1</c-><c- p>;</c-></code></p>
<pre class="highlight"><code class="highlight"><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- 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- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
</code></pre>
    <p><em>Effects:</em> Equivalent to: <code class="highlight"><c- k>return</c-> <c- nf>fetch_sub</c-><c- p>(</c-><c- mi>1</c-><c- p>)</c-> <c- o>-</c-> <c- mi>1</c-><c- p>;</c-></code></p>
    <p>Non-member functions [<strong>atomics.nonmembers</strong>]</p>
    <p>A non-member function template whose name matches the pattern <code class="highlight"><c- n>atomic_</c-><i><c- n>f</c-></i></code> or the pattern <code class="highlight"><c- n>atomic_</c-><i><c- n>f</c-></i><c- n>_explicit</c-></code> invokes the member function <code class="highlight"><i><c- n>f</c-></i></code>, with the value of the first parameter as the object expression and the values of the remaining parameters (if any) as the arguments of the member function call, in order. An argument for a parameter of type <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>::</c-><c- n>value_type</c-><c- o>*</c-></code> is dereferenced when passed to the member function call. If no such member function exists, the program is ill-formed.</p>
<pre class="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->
  <c- b><c- b>void</c-></c-> <c- n><c- n>atomic_init</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- n><c- n>object</c-></c-><c- p><c- p>,</c-></c-> <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- n><c- n>desired</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>T</c-></c-><c- o><c- o>></c-></c->
  <c- b><c- b>void</c-></c-> <c- n><c- n>atomic_init</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- n><c- n>object</c-></c-><c- p><c- p>,</c-></c-> <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- n><c- n>desired</c-></c-><c- p><c- p>)</c-></c-> <c- k><c- k>noexcept</c-></c-><c- p><c- p>;</c-></c->
</code></pre>
    <p><em>Effects:</em> Non-atomically initializes <code class="highlight"><c- o>*</c-><c- n>object</c-></code> with value <code class="highlight"><c- n>desired</c-></code>. This function shall only be applied to objects that have been default constructed, and then only once. [ <em>Note:</em> These semantics ensure compatibility with C. —<em>end note</em> ] [ <em>Note:</em> Concurrent access from another thread, even via an atomic operation, constitutes a data race.  —<em>end note</em> ]</p>
    <ins><em>Constraints:</em> <code class="highlight"><c- n>is_volatile</c-><c- o>&lt;</c-><c- n>T</c-><c- o>></c-></code> is <code class="highlight">false</code>, or <code class="highlight"><c- n>atomic</c-><c- o>&lt;</c-><c- n>T</c-><c- o>>::</c-><c- n>is_always_lock_free</c-></code> is <code class="highlight">true</code>.</ins>
    <p>[ <em>Note:</em> The non-member functions enable programmers to write code that can be compiled as either C or C++, for example in a shared header file.  —<em>end note</em> ]</p>
   </blockquote>
   <h3 class="heading settled" data-level="3.19" id="annexD"><span class="secno">3.19. </span><span class="content">Annex D</span><a class="self-link" href="#annexD"></a></h3>
   <p>All mentions of deprecation in language clauses, and all deletions in library
clauses above should be added to Annex D under [<strong>depr.volatile</strong>], such that <code class="highlight"><c- k>volatile</c-></code> is now deprecated in these use cases.</p>
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  <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-p1152r0">[P1152R0]
   <dd>JF Bastien. <a href="https://wg21.link/p1152r0">Deprecating volatile</a>. 1 October 2018. URL: <a href="https://wg21.link/p1152r0">https://wg21.link/p1152r0</a>
   <dt id="biblio-p1152r1">[P1152R1]
   <dd>JF Bastien. <a href="https://wg21.link/p1152r1">Deprecating volatile</a>. 20 January 2019. URL: <a href="https://wg21.link/p1152r1">https://wg21.link/p1152r1</a>
   <dt id="biblio-p1369r0">[P1369R0]
   <dd>Walter E. Brown. <a href="https://wg21.link/p1369r0">Guidelines for Formulating Library Semantics Specifications</a>. 25 November 2018. URL: <a href="https://wg21.link/p1369r0">https://wg21.link/p1369r0</a>
   <dt id="biblio-p1382r0">[P1382R0]
   <dd>Paul Mckenney; JF Bastien. <a href="http://wg21.link/P1382R0">volatile_load&lt;T> and volatile_store&lt;T></a>. URL: <a href="http://wg21.link/P1382R0">http://wg21.link/P1382R0</a>
  </dl>