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    CWG Issue 2652</TITLE>
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<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="2652"></A><H4>2652.
  
Overbroad definition of <TT>__STDCPP_BFLOAT16_T__</TT>
</H4>
<B>Section: </B>15.12&#160; [<A href="https://wg21.link/cpp.predefined">cpp.predefined</A>]
 &#160;&#160;&#160;

 <B>Status: </B>C++23
 &#160;&#160;&#160;

 <B>Submitter: </B>US
 &#160;&#160;&#160;

 <B>Date: </B>2022-11-03<BR><BR>


<A href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2022/p2720r0.pdf#US31-071">P2720R0 comment
  US&#160;31-071<BR></A>

<P>[Accepted at the November, 2022 meeting.]</P>

<P>
The wording for the predefined macro <TT>__STDCPP_BFLOAT16_T__</TT> added by
P1467 can be interpreted more broadly than was intended.
</P>

<P><B>Proposed resolution (approved by CWG 2022-11-08):</B></P>

<P>Change in 15.12 [<A href="https://wg21.link/cpp.predefined#1">cpp.predefined</A>] paragraph 1 as follows:</P>

<BLOCKQUOTE>

<P><TT>__STDCPP_BFLOAT16_T__</TT></P> Defined as the integer literal 1
if and only if the implementation supports an extended floating-point
type with the properties <INS>of the <I>typedef-name</I>
<TT>std::bfloat16_t</TT> as</INS> described in
6.9.3 [<A href="https://wg21.link/basic.extended.fp">basic.extended.fp</A>].

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