<HTML>
<HEAD>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<TITLE>
    CWG Issue 2723</TITLE>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<STYLE TYPE="text/css">
  INS { text-decoration:none; font-weight:bold; background-color:#A0FFA0 }
  .INS { text-decoration:none; background-color:#D0FFD0 }
  DEL { text-decoration:line-through; background-color:#FFA0A0 }
  .DEL { text-decoration:line-through; background-color: #FFD0D0 }
  @media (prefers-color-scheme: dark) {
    HTML { background-color:#202020; color:#f0f0f0; }
    A { color:#5bc0ff; }
    A:visited { color:#c6a8ff; }
    A:hover, a:focus { color:#afd7ff; }
    INS { background-color:#033a16; color:#aff5b4; }
    .INS { background-color: #033a16; }
    DEL { background-color:#67060c; color:#ffdcd7; }
    .DEL { background-color:#67060c; }
  }
  SPAN.cmnt { font-family:Times; font-style:italic }
</STYLE>
</HEAD>
<BODY>
<P><EM>This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21
  Core Issues List revision 118b.
  See http://www.open-std.org/jtc1/sc22/wg21/ for the official
  list.</EM></P>
<P>2025-09-28</P>
<HR>
<A NAME="2723"></A><H4>2723.
  
Range of representable values for floating-point types
</H4>
<B>Section: </B>6.9.2&#160; [<A href="https://wg21.link/basic.fundamental">basic.fundamental</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD7
 &#160;&#160;&#160;

 <B>Submitter: </B>Jiang An
 &#160;&#160;&#160;

 <B>Date: </B>2023-04-21<BR>


<P>[Accepted as a DR at the June, 2023 meeting.]</P>

<P>The range of representable values is defined for integer types, but
not for floating-point types.  This term is used in
5.13.4 [<A href="https://wg21.link/lex.fcon#3">lex.fcon</A>] paragraph 3 as well as in the library,
e.g. in 28.2.3 [<A href="https://wg21.link/charconv.from.chars">charconv.from.chars</A>] and
28.3.4.3.2.3 [<A href="https://wg21.link/facet.num.get.virtuals">facet.num.get.virtuals</A>].</P>

<P>The C standard contains a suitable definition that we should
inherit.</P>

<P><B>Proposed resolution (approved by CWG 2023-05-12):</B></P>

<P>Add a new paragraph after 6.9.2 [<A href="https://wg21.link/basic.fundamental#12">basic.fundamental</A>] paragraph 12 as follows:</P>

<BLOCKQUOTE>

<P>... Except as specified in 6.9.3 [<A href="https://wg21.link/basic.extended.fp">basic.extended.fp</A>], the object and
value representations and accuracy of operations of floating-point
types are implementation-defined.</P>

<P class="ins">
The minimum range of representable values for a floating-point type is
the most negative finite floating-point number representable in that
type through the most positive finite floating-point number
representable in that type. In addition, if negative infinity is
representable in a type, the range of that type is extended to all
negative real numbers; likewise, if positive infinity is representable
in a type, the range of that type is extended to all positive real
numbers. [ Note: Since negative and positive infinity are
representable in ISO/IEC/IEEE 60559 formats, all real numbers lie
within the range of representable values of a floating-point type
adhering to ISO/IEC/IEEE 60559. ]
</P>

</BLOCKQUOTE>

<BR><BR>
</BODY>
</HTML>
