New issue from Aiden Grossman: "std::dynamic_extent should also be defined in <mdspan>"

Author: Dani-Hub

xml/issue4275.xml

@@ -0,0 +1,50 @@
+<?xml version='1.0' encoding='utf-8' standalone='no'?>
+<!DOCTYPE issue SYSTEM "lwg-issue.dtd">
+
+<issue num="4275" status="New">
+<title>`std::dynamic_extent` should also be defined in <tt>&lt;mdspan&gt;</tt></title>
+<section>
+<sref ref="[time.hms.members]"/>
+</section>
+<submitter>Aiden Grossman</submitter>
+<date>06 Jun 2025</date>
+<priority>99</priority>
+
+<discussion>
+<p>
+`std::dynamic_extent` can be used in certain circumstances in `std::mdspan`, 
+such as with padded layouts. However, `std::dynamic_extent` is currently only 
+defined in <tt>&lt;span&gt;</tt> which necessitates including <tt>&lt;span&gt;</tt> 
+solely for the `std::dynamic_extent` definition.
+</p>
+</discussion>
+
+<resolution>
+<p>
+This wording is relative to <paper num="N5008"/>.
+</p>
+
+<ol>
+<li><p>Modify <sref ref="[mdspan.syn]"/>, header <tt>&lt;span&gt;</tt> synopsis, as indicated:</p>
+
+<blockquote>
+<pre>
+<i>// all freestanding</i>
+namespace std {
+  <ins><i>// constants</i></ins>
+  <ins>inline constexpr size_t dynamic_extent = numeric_limits&lt;size_t&gt;::max();</ins>
+  
+  <i>// <sref ref="[mdspan.extents]"/>, class template extents</i>
+  template&lt;class IndexType, size_t... Extents&gt;
+  class extents;
+
+  [&hellip;]
+}
+</pre>
+</blockquote>
+</li>
+
+</ol>
+</resolution>
+
+</issue>