libstdc++: Add all supported headers to lists in the manual

libstdc++-v3/ChangeLog:

	* doc/xml/manual/using.xml: Update tables of supported headers.
	* doc/html/*: Regenerate.

2 files changed, 43 insertions, 17 deletions

diff --git a/libstdc++-v3/doc/html/manual/index.html b/libstdc++-v3/doc/html/manual/index.html
index 1639c95..ef58061 100644
--- a/libstdc++-v3/doc/html/manual/index.html
+++ b/libstdc++-v3/doc/html/manual/index.html
@@ -145,7 +145,7 @@ Support for C++11 dialect.
 	  </a></dt><dt>21.10. <a href="policy_data_structures_design.html#id-1.3.5.8.4.3.3.3.23">Non-unique Mapping Containers</a></dt><dt>21.11. <a href="policy_data_structures_design.html#id-1.3.5.8.4.3.4.3.5">Point Iterator Hierarchy</a></dt><dt>21.12. <a href="policy_data_structures_design.html#id-1.3.5.8.4.3.4.4.5">Invalidation Guarantee Tags Hierarchy</a></dt><dt>21.13. <a href="policy_data_structures_design.html#id-1.3.5.8.4.3.5.7.4">Container Tag Hierarchy</a></dt><dt>21.14. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.2.2.3">Hash functions, ranged-hash functions, and
 	      range-hashing functions</a></dt><dt>21.15. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.2.5.3.4">Insert hash sequence diagram</a></dt><dt>21.16. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.2.5.3.6">Insert hash sequence diagram with a null policy</a></dt><dt>21.17. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.2.5.5.5">Hash policy class diagram</a></dt><dt>21.18. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.3.4.7">Balls and bins</a></dt><dt>21.19. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.3.5.3.6">Insert resize sequence diagram</a></dt><dt>21.20. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.3.5.3.9">Standard resize policy trigger sequence
 		diagram</a></dt><dt>21.21. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.3.5.3.10">Standard resize policy size sequence
-		diagram</a></dt><dt>21.22. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.3.3.2.5">Tree node invariants</a></dt><dt>21.23. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.3.3.2.8">Tree node invalidation</a></dt><dt>21.24. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.3.3.2.11.3">A tree and its update policy</a></dt><dt>21.25. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.3.3.2.11.8">Restoring node invariants</a></dt><dt>21.26. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.3.3.2.11.10">Insert update sequence</a></dt><dt>21.27. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.3.3.2.11.20">Useless update path</a></dt><dt>21.28. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.4.3.2.10">A PATRICIA trie</a></dt><dt>21.29. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.4.3.3.5">A trie and its update policy</a></dt><dt>21.30. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.5.3.3.3">A simple list</a></dt><dt>21.31. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.5.3.3.6">The counter algorithm</a></dt><dt>21.32. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.6.3.3.3">Underlying Priority-Queue Data-Structures.</a></dt><dt>21.33. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.6.3.4.4">Priority-Queue Data-Structure Tags.</a></dt><dt>B.1. <a href="appendix_porting.html#fig.build_hacking.deps">Configure and Build File Dependencies</a></dt></dl></div><div class="list-of-tables"><p><strong>List of Tables</strong></p><dl><dt>1.1. <a href="status.html#table.cxx98_status">C++ 1998/2003 Implementation Status</a></dt><dt>1.2. <a href="status.html#table.cxx11_status">C++ 2011 Implementation Status</a></dt><dt>1.3. <a href="status.html#table.cxx14_status">C++ 2014 Implementation Status</a></dt><dt>1.4. <a href="status.html#table.ts_status">C++ Technical Specifications Implementation Status</a></dt><dt>1.5. <a href="status.html#table.cxx17_features">C++ 2017 Library Features</a></dt><dt>1.6. <a href="status.html#table.cxx17_status">C++ 2017 Implementation Status</a></dt><dt>1.7. <a href="status.html#table.cxx17_ts_status">C++ Technical Specifications Implementation Status</a></dt><dt>1.8. <a href="status.html#table.par2ts_simd_support">Support for Extended ABI Tags</a></dt><dt>1.9. <a href="status.html#table.cxx20_features">C++ 2020 Library Features</a></dt><dt>1.10. <a href="status.html#table.cxx23_features">C++ 2023 Library Features</a></dt><dt>1.11. <a href="status.html#table.tr1_status">C++ TR1 Implementation Status</a></dt><dt>1.12. <a href="status.html#table.decfp_status">C++ TR 24733 Implementation Status</a></dt><dt>1.13. <a href="status.html#table.specfun_status">C++ Special Functions Implementation Status</a></dt><dt>3.1. <a href="using.html#table.cmd_options">C++ Command Options</a></dt><dt>3.2. <a href="using_headers.html#table.cxx98_headers">C++ 1998 Library Headers</a></dt><dt>3.3. <a href="using_headers.html#table.cxx98_cheaders">C++ 1998 Library Headers for C Library Facilities</a></dt><dt>3.4. <a href="using_headers.html#table.cxx98_deprheaders">C++ 1998 Deprecated Library Header</a></dt><dt>3.5. <a href="using_headers.html#table.cxx11_headers">C++ 2011 Library Headers</a></dt><dt>3.6. <a href="using_headers.html#table.cxx11_cheaders">C++ 2011 Library Headers for C Library Facilities</a></dt><dt>3.7. <a href="using_headers.html#table.cxx14_headers">C++ 2014 Library Header</a></dt><dt>3.8. <a href="using_headers.html#table.cxx17_headers">C++ 2017 Library Headers</a></dt><dt>3.9. <a href="using_headers.html#table.cxx20_headers">C++ 2020 Library Headers</a></dt><dt>3.10. <a href="using_headers.html#table.cxx20_deprheaders">C++ 2020 Obsolete Headers</a></dt><dt>3.11. <a href="using_headers.html#table.filesystemts_headers">File System TS Header</a></dt><dt>3.12. <a href="using_headers.html#table.libfundts_headers">Library Fundamentals TS Headers</a></dt><dt>3.13. <a href="using_headers.html#table.tr1_headers">C++ TR 1 Library Headers</a></dt><dt>3.14. <a href="using_headers.html#table.tr1_cheaders">C++ TR 1 Library Headers for C Library Facilities</a></dt><dt>3.15. <a href="using_headers.html#table.decfp_headers">C++ TR 24733 Decimal Floating-Point Header</a></dt><dt>3.16. <a href="using_headers.html#table.abi_headers">C++ ABI Headers</a></dt><dt>3.17. <a href="using_headers.html#table.ext_headers">Extension Headers</a></dt><dt>3.18. <a href="using_headers.html#table.debug_headers">Extension Debug Headers</a></dt><dt>3.19. <a href="using_headers.html#table.parallel_headers">Extension Parallel Headers</a></dt><dt>17.1. <a href="debug_mode_using.html#table.debug_mode_containers">Debugging Containers</a></dt><dt>17.2. <a href="debug_mode_using.html#table.debug_mode_containers_cxx11">Debugging Containers C++11</a></dt><dt>18.1. <a href="parallel_mode_using.html#table.parallel_algos">Parallel Algorithms</a></dt><dt>20.1. <a href="bitmap_allocator_impl.html#table.bitmap_alloc">Bitmap Allocator Memory Map</a></dt><dt>B.1. <a href="documentation_hacking.html#table.doxygen_prereq">Doxygen Prerequisites</a></dt><dt>B.2. <a href="documentation_hacking.html#table.doxygen_cmp">HTML to Doxygen Markup Comparison</a></dt><dt>B.3. <a href="documentation_hacking.html#table.docbook_prereq">Docbook Prerequisites</a></dt><dt>B.4. <a href="documentation_hacking.html#table.docbook_cmp">HTML to Docbook XML Markup Comparison</a></dt><dt>B.5. <a href="documentation_hacking.html#table.docbook_elem">Docbook XML Element Use</a></dt><dt>B.6. <a href="api.html#table.extension_allocators">Extension Allocators</a></dt><dt>B.7. <a href="api.html#table.extension_allocators2">Extension Allocators Continued</a></dt></dl></div><div class="list-of-equations"><p><strong>List of Equations</strong></p><dl><dt>21.1. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.2.2.15">Ranged Hash Function</a></dt><dt>21.2. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.2.3.3">Range-Hashing, Division Method</a></dt><dt>21.3. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.2.3.9">Division via Prime Modulo</a></dt><dt>21.4. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.2.3.11">Division via Bit Mask</a></dt><dt>21.5. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.2.4.7">
+		diagram</a></dt><dt>21.22. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.3.3.2.5">Tree node invariants</a></dt><dt>21.23. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.3.3.2.8">Tree node invalidation</a></dt><dt>21.24. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.3.3.2.11.3">A tree and its update policy</a></dt><dt>21.25. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.3.3.2.11.8">Restoring node invariants</a></dt><dt>21.26. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.3.3.2.11.10">Insert update sequence</a></dt><dt>21.27. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.3.3.2.11.20">Useless update path</a></dt><dt>21.28. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.4.3.2.10">A PATRICIA trie</a></dt><dt>21.29. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.4.3.3.5">A trie and its update policy</a></dt><dt>21.30. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.5.3.3.3">A simple list</a></dt><dt>21.31. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.5.3.3.6">The counter algorithm</a></dt><dt>21.32. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.6.3.3.3">Underlying Priority-Queue Data-Structures.</a></dt><dt>21.33. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.6.3.4.4">Priority-Queue Data-Structure Tags.</a></dt><dt>B.1. <a href="appendix_porting.html#fig.build_hacking.deps">Configure and Build File Dependencies</a></dt></dl></div><div class="list-of-tables"><p><strong>List of Tables</strong></p><dl><dt>1.1. <a href="status.html#table.cxx98_status">C++ 1998/2003 Implementation Status</a></dt><dt>1.2. <a href="status.html#table.cxx11_status">C++ 2011 Implementation Status</a></dt><dt>1.3. <a href="status.html#table.cxx14_status">C++ 2014 Implementation Status</a></dt><dt>1.4. <a href="status.html#table.ts_status">C++ Technical Specifications Implementation Status</a></dt><dt>1.5. <a href="status.html#table.cxx17_features">C++ 2017 Library Features</a></dt><dt>1.6. <a href="status.html#table.cxx17_status">C++ 2017 Implementation Status</a></dt><dt>1.7. <a href="status.html#table.cxx17_ts_status">C++ Technical Specifications Implementation Status</a></dt><dt>1.8. <a href="status.html#table.par2ts_simd_support">Support for Extended ABI Tags</a></dt><dt>1.9. <a href="status.html#table.cxx20_features">C++ 2020 Library Features</a></dt><dt>1.10. <a href="status.html#table.cxx23_features">C++ 2023 Library Features</a></dt><dt>1.11. <a href="status.html#table.tr1_status">C++ TR1 Implementation Status</a></dt><dt>1.12. <a href="status.html#table.decfp_status">C++ TR 24733 Implementation Status</a></dt><dt>1.13. <a href="status.html#table.specfun_status">C++ Special Functions Implementation Status</a></dt><dt>3.1. <a href="using.html#table.cmd_options">C++ Command Options</a></dt><dt>3.2. <a href="using_headers.html#table.cxx98_headers">C++ 1998 Library Headers</a></dt><dt>3.3. <a href="using_headers.html#table.cxx98_cheaders">C++ 1998 Library Headers for C Library Facilities</a></dt><dt>3.4. <a href="using_headers.html#table.cxx98_deprheaders">C++ 1998 Deprecated Library Header</a></dt><dt>3.5. <a href="using_headers.html#table.cxx11_headers">C++ 2011 Library Headers</a></dt><dt>3.6. <a href="using_headers.html#table.cxx11_cheaders">C++ 2011 Library Headers for C Library Facilities</a></dt><dt>3.7. <a href="using_headers.html#table.cxx14_headers">C++ 2014 Library Header</a></dt><dt>3.8. <a href="using_headers.html#table.cxx17_headers">C++ 2017 Library Headers</a></dt><dt>3.9. <a href="using_headers.html#table.cxx20_headers">C++ 2020 Library Headers</a></dt><dt>3.10. <a href="using_headers.html#table.cxx20_deprheaders">C++ 2020 Obsolete Headers</a></dt><dt>3.11. <a href="using_headers.html#table.cxx23_headers">C++ 2023 Library Headers</a></dt><dt>3.12. <a href="using_headers.html#table.cxx26_headers">C++ 2026 Library Headers</a></dt><dt>3.13. <a href="using_headers.html#table.filesystemts_headers">File System TS Header</a></dt><dt>3.14. <a href="using_headers.html#table.libfundts_headers">Library Fundamentals TS Headers</a></dt><dt>3.15. <a href="using_headers.html#table.networkingts_headers">Networking TS Headers</a></dt><dt>3.16. <a href="using_headers.html#table.tr1_headers">C++ TR 1 Library Headers</a></dt><dt>3.17. <a href="using_headers.html#table.tr1_cheaders">C++ TR 1 Library Headers for C Library Facilities</a></dt><dt>3.18. <a href="using_headers.html#table.decfp_headers">C++ TR 24733 Decimal Floating-Point Header</a></dt><dt>3.19. <a href="using_headers.html#table.abi_headers">C++ ABI Headers</a></dt><dt>3.20. <a href="using_headers.html#table.ext_headers">Extension Headers</a></dt><dt>3.21. <a href="using_headers.html#table.debug_headers">Extension Debug Headers</a></dt><dt>3.22. <a href="using_headers.html#table.parallel_headers">Extension Parallel Headers</a></dt><dt>17.1. <a href="debug_mode_using.html#table.debug_mode_containers">Debugging Containers</a></dt><dt>17.2. <a href="debug_mode_using.html#table.debug_mode_containers_cxx11">Debugging Containers C++11</a></dt><dt>18.1. <a href="parallel_mode_using.html#table.parallel_algos">Parallel Algorithms</a></dt><dt>20.1. <a href="bitmap_allocator_impl.html#table.bitmap_alloc">Bitmap Allocator Memory Map</a></dt><dt>B.1. <a href="documentation_hacking.html#table.doxygen_prereq">Doxygen Prerequisites</a></dt><dt>B.2. <a href="documentation_hacking.html#table.doxygen_cmp">HTML to Doxygen Markup Comparison</a></dt><dt>B.3. <a href="documentation_hacking.html#table.docbook_prereq">Docbook Prerequisites</a></dt><dt>B.4. <a href="documentation_hacking.html#table.docbook_cmp">HTML to Docbook XML Markup Comparison</a></dt><dt>B.5. <a href="documentation_hacking.html#table.docbook_elem">Docbook XML Element Use</a></dt><dt>B.6. <a href="api.html#table.extension_allocators">Extension Allocators</a></dt><dt>B.7. <a href="api.html#table.extension_allocators2">Extension Allocators Continued</a></dt></dl></div><div class="list-of-equations"><p><strong>List of Equations</strong></p><dl><dt>21.1. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.2.2.15">Ranged Hash Function</a></dt><dt>21.2. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.2.3.3">Range-Hashing, Division Method</a></dt><dt>21.3. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.2.3.9">Division via Prime Modulo</a></dt><dt>21.4. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.2.3.11">Division via Bit Mask</a></dt><dt>21.5. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.2.4.7">
 		A Standard String Hash Function
 	      </a></dt><dt>21.6. <a href="policy_data_structures_design.html#id-1.3.5.8.4.4.2.3.2.4.12">
 		Only k String DNA Hash
diff --git a/libstdc++-v3/doc/html/manual/using_headers.html b/libstdc++-v3/doc/html/manual/using_headers.html
index da86cf7..a267e08 100644
--- a/libstdc++-v3/doc/html/manual/using_headers.html
+++ b/libstdc++-v3/doc/html/manual/using_headers.html
@@ -55,41 +55,67 @@ Unless specified otherwise below, they are also available in later modes
 (C++20 etc).
 </p><p></p><div class="table"><a id="table.cxx17_headers"></a><p class="title"><strong>Table 3.8. C++ 2017 Library Headers</strong></p><div class="table-contents"><table class="table" summary="C++ 2017 Library Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">any</code></td><td align="left"><code class="filename">charconv</code></td><td align="left"><code class="filename">execution</code></td><td align="left"><code class="filename">filesystem</code></td><td align="left"><code class="filename">memory_resource</code></td></tr><tr><td align="left"><code class="filename">optional</code></td><td align="left"><code class="filename">string_view</code></td><td align="left"><code class="filename">variant</code></td><td colspan="2" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p>
 <a class="xref" href="using_headers.html#table.cxx20_headers" title="Table 3.9. C++ 2020 Library Headers">Table 3.9, “C++ 2020 Library Headers”</a>
-shows the C++2a include files.
-These are available in C++2a compilation
-mode, i.e. <code class="literal">-std=c++2a</code> or <code class="literal">-std=gnu++2a</code>.
+shows the C++20 include files.
+These are available in C++20 compilation
+mode, i.e. <code class="literal">-std=c++20</code> or <code class="literal">-std=gnu++20</code>.
 Including these headers in earlier modes will not result in
 compilation errors, but will not define anything.
 
-</p><p></p><div class="table"><a id="table.cxx20_headers"></a><p class="title"><strong>Table 3.9. C++ 2020 Library Headers</strong></p><div class="table-contents"><table class="table" summary="C++ 2020 Library Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /></colgroup><tbody><tr><td align="left"><code class="filename">bit</code></td><td align="left"><code class="filename">version</code></td></tr></tbody></table></div></div><br class="table-break" /><p>
-  The following headers have been removed in the C++2a working draft.
+</p><p></p><div class="table"><a id="table.cxx20_headers"></a><p class="title"><strong>Table 3.9. C++ 2020 Library Headers</strong></p><div class="table-contents"><table class="table" summary="C++ 2020 Library Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">barrier</code></td><td align="left"><code class="filename">bit</code></td><td align="left"><code class="filename">charconv</code></td><td align="left"><code class="filename">compare</code></td><td align="left"><code class="filename">concepts</code></td></tr><tr><td align="left"><code class="filename">coroutine</code></td><td align="left"><code class="filename">format</code></td><td align="left"><code class="filename">latch</code></td><td align="left"><code class="filename">numbers</code></td><td align="left"><code class="filename">ranges</code></td></tr><tr><td align="left"><code class="filename">semaphore</code></td><td align="left"><code class="filename">source_location</code></td><td align="left"><code class="filename">span</code></td><td align="left"><code class="filename">stop_token</code></td><td align="left"><code class="filename">syncstream</code></td></tr><tr><td align="left"><code class="filename">version</code></td><td colspan="4" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p>
+  The following headers have been removed in the C++20 standard.
   They are still available when using this implementation, but in future
-  they might start to produce warnings or errors when included in C++2a mode.
+  they might start to produce warnings or errors when included in C++20 mode.
   Programs that intend to be portable should not include them.
 </p><div class="table"><a id="table.cxx20_deprheaders"></a><p class="title"><strong>Table 3.10. C++ 2020 Obsolete Headers</strong></p><div class="table-contents"><table class="table" summary="C++ 2020 Obsolete Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">ccomplex</code></td><td align="left"><code class="filename">ciso646</code></td><td align="left"><code class="filename">cstdalign</code></td><td align="left"><code class="filename">cstdbool</code></td><td align="left"><code class="filename">ctgmath</code></td></tr></tbody></table></div></div><br class="table-break" /><p>
-<a class="xref" href="using_headers.html#table.filesystemts_headers" title="Table 3.11. File System TS Header">Table 3.11, “File System TS Header”</a>,
+<a class="xref" href="using_headers.html#table.cxx23_headers" title="Table 3.11. C++ 2023 Library Headers">Table 3.11, “C++ 2023 Library Headers”</a>
+shows the C++23 include files.
+These are available in C++23 compilation
+mode, i.e. <code class="literal">-std=c++23</code> or <code class="literal">-std=gnu++23</code>.
+Including these headers in earlier modes will not result in
+compilation errors, but will not define anything.
+
+</p><p></p><div class="table"><a id="table.cxx23_headers"></a><p class="title"><strong>Table 3.11. C++ 2023 Library Headers</strong></p><div class="table-contents"><table class="table" summary="C++ 2023 Library Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">expected</code></td><td align="left"><code class="filename">generator</code></td><td align="left"><code class="filename">print</code></td><td align="left"><code class="filename">spanstream</code></td><td align="left"><code class="filename">stacktrace</code></td></tr><tr><td align="left"><code class="filename">stdatomic.h</code></td><td align="left"><code class="filename">stdfloat</code></td><td colspan="3" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p>
+<a class="xref" href="using_headers.html#table.cxx26_headers" title="Table 3.12. C++ 2026 Library Headers">Table 3.12, “C++ 2026 Library Headers”</a>
+shows the C++26 include files.
+These are available in C++26 compilation
+mode, i.e. <code class="literal">-std=c++26</code> or <code class="literal">-std=gnu++26</code>.
+Including these headers in earlier modes will not result in
+compilation errors, but will not define anything.
+
+</p><p></p><div class="table"><a id="table.cxx26_headers"></a><p class="title"><strong>Table 3.12. C++ 2026 Library Headers</strong></p><div class="table-contents"><table class="table" summary="C++ 2026 Library Headers" border="1"><colgroup><col align="left" class="c1" /></colgroup><tbody><tr><td align="left"><code class="filename">text_encoding</code></td></tr></tbody></table></div></div><br class="table-break" /><p>
+<a class="xref" href="using_headers.html#table.filesystemts_headers" title="Table 3.13. File System TS Header">Table 3.13, “File System TS Header”</a>,
 shows the additional include file define by the
-File System Technical Specification, ISO/IEC TS 18822.
+File System Technical Specification, ISO/IEC TS 18822:2015.
 This is available in C++11 and later compilation modes.
 Including this header in earlier modes will not result in
 compilation errors, but will not define anything.
-</p><p></p><div class="table"><a id="table.filesystemts_headers"></a><p class="title"><strong>Table 3.11. File System TS Header</strong></p><div class="table-contents"><table class="table" summary="File System TS Header" border="1"><colgroup><col align="left" class="c1" /></colgroup><tbody><tr><td align="left"><code class="filename">experimental/filesystem</code></td></tr></tbody></table></div></div><br class="table-break" /><p>
-<a class="xref" href="using_headers.html#table.libfundts_headers" title="Table 3.12. Library Fundamentals TS Headers">Table 3.12, “Library Fundamentals TS Headers”</a>,
+</p><p></p><div class="table"><a id="table.filesystemts_headers"></a><p class="title"><strong>Table 3.13. File System TS Header</strong></p><div class="table-contents"><table class="table" summary="File System TS Header" border="1"><colgroup><col align="left" class="c1" /></colgroup><tbody><tr><td align="left"><code class="filename">experimental/filesystem</code></td></tr></tbody></table></div></div><br class="table-break" /><p>
+<a class="xref" href="using_headers.html#table.libfundts_headers" title="Table 3.14. Library Fundamentals TS Headers">Table 3.14, “Library Fundamentals TS Headers”</a>,
 shows the additional include files define by the C++ Extensions for
-Library Fundamentals Technical Specification, ISO/IEC TS 19568.
+Library Fundamentals Technical Specification, ISO/IEC TS 19568:2015,
+ISO/IEC TS 19568:2017, and ISO/IEC TS 19568:2024.
+These are available in C++14 and later compilation modes, except for
+<code class="filename">&lt;experimental/scope&gt;</code>
+which is available in C++20 and later compilation modes.
+Including these headers in earlier modes will not result in
+compilation errors, but will not define anything.
+</p><p></p><div class="table"><a id="table.libfundts_headers"></a><p class="title"><strong>Table 3.14. Library Fundamentals TS Headers</strong></p><div class="table-contents"><table class="table" summary="Library Fundamentals TS Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">experimental/algorithm</code></td><td align="left"><code class="filename">experimental/any</code></td><td align="left"><code class="filename">experimental/array</code></td><td align="left"><code class="filename">experimental/chrono</code></td><td align="left"><code class="filename">experimental/deque</code></td></tr><tr><td align="left"><code class="filename">experimental/forward_list</code></td><td align="left"><code class="filename">experimental/functional</code></td><td align="left"><code class="filename">experimental/iterator</code></td><td align="left"><code class="filename">experimental/list</code></td><td align="left"><code class="filename">experimental/map</code></td></tr><tr><td align="left"><code class="filename">experimental/memory</code></td><td align="left"><code class="filename">experimental/memory_resource</code></td><td align="left"><code class="filename">experimental/numeric</code></td><td align="left"><code class="filename">experimental/optional</code></td><td align="left"><code class="filename">experimental/propagate_const</code></td></tr><tr><td align="left"><code class="filename">experimental/random</code></td><td align="left"><code class="filename">experimental/ratio</code></td><td align="left"><code class="filename">experimental/regex</code></td><td align="left"><code class="filename">experimental/scope</code></td><td align="left"><code class="filename">experimental/set</code></td></tr><tr><td align="left"><code class="filename">experimental/source_location</code></td><td align="left"><code class="filename">experimental/string</code></td><td align="left"><code class="filename">experimental/string_view</code></td><td align="left"><code class="filename">experimental/system_error</code></td><td align="left"><code class="filename">experimental/tuple</code></td></tr><tr><td align="left"><code class="filename">experimental/type_traits</code></td><td align="left"><code class="filename">experimental/unordered_map</code></td><td align="left"><code class="filename">experimental/unordered_set</code></td><td align="left"><code class="filename">experimental/utility</code></td><td align="left"><code class="filename">experimental/vector</code></td></tr></tbody></table></div></div><br class="table-break" /><p>
+<a class="xref" href="using_headers.html#table.networkingts_headers" title="Table 3.15. Networking TS Headers">Table 3.15, “Networking TS Headers”</a>,
+shows the additional include files define by the
+Networking Technical Specification, ISO/IEC TS 19216:2018.
 These are available in C++14 and later compilation modes.
 Including these headers in earlier modes will not result in
 compilation errors, but will not define anything.
-</p><p></p><div class="table"><a id="table.libfundts_headers"></a><p class="title"><strong>Table 3.12. Library Fundamentals TS Headers</strong></p><div class="table-contents"><table class="table" summary="Library Fundamentals TS Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">experimental/algorithm</code></td><td align="left"><code class="filename">experimental/any</code></td><td align="left"><code class="filename">experimental/array</code></td><td align="left"><code class="filename">experimental/chrono</code></td><td align="left"><code class="filename">experimental/deque</code></td></tr><tr><td align="left"><code class="filename">experimental/forward_list</code></td><td align="left"><code class="filename">experimental/functional</code></td><td align="left"><code class="filename">experimental/iterator</code></td><td align="left"><code class="filename">experimental/list</code></td><td align="left"><code class="filename">experimental/map</code></td></tr><tr><td align="left"><code class="filename">experimental/memory</code></td><td align="left"><code class="filename">experimental/memory_resource</code></td><td align="left"><code class="filename">experimental/numeric</code></td><td align="left"><code class="filename">experimental/optional</code></td><td align="left"><code class="filename">experimental/propagate_const</code></td></tr><tr><td align="left"><code class="filename">experimental/random</code></td><td align="left"><code class="filename">experimental/ratio</code></td><td align="left"><code class="filename">experimental/regex</code></td><td align="left"><code class="filename">experimental/set</code></td><td align="left"><code class="filename">experimental/source_location</code></td></tr><tr><td align="left"><code class="filename">experimental/string</code></td><td align="left"><code class="filename">experimental/string_view</code></td><td align="left"><code class="filename">experimental/system_error</code></td><td align="left"><code class="filename">experimental/tuple</code></td><td align="left"><code class="filename">experimental/type_traits</code></td></tr><tr><td align="left"><code class="filename">experimental/unordered_map</code></td><td align="left"><code class="filename">experimental/unordered_set</code></td><td align="left"><code class="filename">experimental/utility</code></td><td align="left"><code class="filename">experimental/vector</code></td><td align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p>
+</p><p></p><div class="table"><a id="table.networkingts_headers"></a><p class="title"><strong>Table 3.15. Networking TS Headers</strong></p><div class="table-contents"><table class="table" summary="Networking TS Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /></colgroup><tbody><tr><td align="left"><code class="filename">experimental/buffer</code></td><td align="left"><code class="filename">experimental/executor</code></td><td align="left"><code class="filename">experimental/internet</code></td><td align="left"><code class="filename">experimental/io_context</code></td></tr><tr><td align="left"><code class="filename">experimental/net</code></td><td align="left"><code class="filename">experimental/netfwd</code></td><td align="left"><code class="filename">experimental/socket</code></td><td align="left"><code class="filename">experimental/timer</code></td></tr></tbody></table></div></div><br class="table-break" /><p>
   In addition, TR1 includes as:
-</p><div class="table"><a id="table.tr1_headers"></a><p class="title"><strong>Table 3.13. C++ TR 1 Library Headers</strong></p><div class="table-contents"><table class="table" summary="C++ TR 1 Library Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">tr1/array</code></td><td align="left"><code class="filename">tr1/complex</code></td><td align="left"><code class="filename">tr1/memory</code></td><td align="left"><code class="filename">tr1/functional</code></td><td align="left"><code class="filename">tr1/random</code></td></tr><tr><td align="left"><code class="filename">tr1/regex</code></td><td align="left"><code class="filename">tr1/tuple</code></td><td align="left"><code class="filename">tr1/type_traits</code></td><td align="left"><code class="filename">tr1/unordered_map</code></td><td align="left"><code class="filename">tr1/unordered_set</code></td></tr><tr><td align="left"><code class="filename">tr1/utility</code></td><td colspan="4" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p></p><div class="table"><a id="table.tr1_cheaders"></a><p class="title"><strong>Table 3.14. C++ TR 1 Library Headers for C Library Facilities</strong></p><div class="table-contents"><table class="table" summary="C++ TR 1 Library Headers for C Library Facilities" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">tr1/ccomplex</code></td><td align="left"><code class="filename">tr1/cfenv</code></td><td align="left"><code class="filename">tr1/cfloat</code></td><td align="left"><code class="filename">tr1/cmath</code></td><td align="left"><code class="filename">tr1/cinttypes</code></td></tr><tr><td align="left"><code class="filename">tr1/climits</code></td><td align="left"><code class="filename">tr1/cstdarg</code></td><td align="left"><code class="filename">tr1/cstdbool</code></td><td align="left"><code class="filename">tr1/cstdint</code></td><td align="left"><code class="filename">tr1/cstdio</code></td></tr><tr><td align="left"><code class="filename">tr1/cstdlib</code></td><td align="left"><code class="filename">tr1/ctgmath</code></td><td align="left"><code class="filename">tr1/ctime</code></td><td align="left"><code class="filename">tr1/cwchar</code></td><td align="left"><code class="filename">tr1/cwctype</code></td></tr></tbody></table></div></div><br class="table-break" /><p>Decimal floating-point arithmetic is available if the C++
+</p><div class="table"><a id="table.tr1_headers"></a><p class="title"><strong>Table 3.16. C++ TR 1 Library Headers</strong></p><div class="table-contents"><table class="table" summary="C++ TR 1 Library Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">tr1/array</code></td><td align="left"><code class="filename">tr1/complex</code></td><td align="left"><code class="filename">tr1/memory</code></td><td align="left"><code class="filename">tr1/functional</code></td><td align="left"><code class="filename">tr1/random</code></td></tr><tr><td align="left"><code class="filename">tr1/regex</code></td><td align="left"><code class="filename">tr1/tuple</code></td><td align="left"><code class="filename">tr1/type_traits</code></td><td align="left"><code class="filename">tr1/unordered_map</code></td><td align="left"><code class="filename">tr1/unordered_set</code></td></tr><tr><td align="left"><code class="filename">tr1/utility</code></td><td colspan="4" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p></p><div class="table"><a id="table.tr1_cheaders"></a><p class="title"><strong>Table 3.17. C++ TR 1 Library Headers for C Library Facilities</strong></p><div class="table-contents"><table class="table" summary="C++ TR 1 Library Headers for C Library Facilities" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">tr1/ccomplex</code></td><td align="left"><code class="filename">tr1/cfenv</code></td><td align="left"><code class="filename">tr1/cfloat</code></td><td align="left"><code class="filename">tr1/cmath</code></td><td align="left"><code class="filename">tr1/cinttypes</code></td></tr><tr><td align="left"><code class="filename">tr1/climits</code></td><td align="left"><code class="filename">tr1/cstdarg</code></td><td align="left"><code class="filename">tr1/cstdbool</code></td><td align="left"><code class="filename">tr1/cstdint</code></td><td align="left"><code class="filename">tr1/cstdio</code></td></tr><tr><td align="left"><code class="filename">tr1/cstdlib</code></td><td align="left"><code class="filename">tr1/ctgmath</code></td><td align="left"><code class="filename">tr1/ctime</code></td><td align="left"><code class="filename">tr1/cwchar</code></td><td align="left"><code class="filename">tr1/cwctype</code></td></tr></tbody></table></div></div><br class="table-break" /><p>Decimal floating-point arithmetic is available if the C++
 compiler supports scalar decimal floating-point types defined via
 <code class="code">__attribute__((mode(SD|DD|LD)))</code>.
-</p><div class="table"><a id="table.decfp_headers"></a><p class="title"><strong>Table 3.15. C++ TR 24733 Decimal Floating-Point Header</strong></p><div class="table-contents"><table class="table" summary="C++ TR 24733 Decimal Floating-Point Header" border="1"><colgroup><col align="left" class="c1" /></colgroup><tbody><tr><td align="left"><code class="filename">decimal/decimal</code></td></tr></tbody></table></div></div><br class="table-break" /><p>
+</p><div class="table"><a id="table.decfp_headers"></a><p class="title"><strong>Table 3.18. C++ TR 24733 Decimal Floating-Point Header</strong></p><div class="table-contents"><table class="table" summary="C++ TR 24733 Decimal Floating-Point Header" border="1"><colgroup><col align="left" class="c1" /></colgroup><tbody><tr><td align="left"><code class="filename">decimal/decimal</code></td></tr></tbody></table></div></div><br class="table-break" /><p>
   Also included are files for the C++ ABI interface:
-</p><div class="table"><a id="table.abi_headers"></a><p class="title"><strong>Table 3.16. C++ ABI Headers</strong></p><div class="table-contents"><table class="table" summary="C++ ABI Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /></colgroup><tbody><tr><td align="left"><code class="filename">cxxabi.h</code></td><td align="left"><code class="filename">cxxabi_forced.h</code></td></tr></tbody></table></div></div><br class="table-break" /><p>
+</p><div class="table"><a id="table.abi_headers"></a><p class="title"><strong>Table 3.19. C++ ABI Headers</strong></p><div class="table-contents"><table class="table" summary="C++ ABI Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /></colgroup><tbody><tr><td align="left"><code class="filename">cxxabi.h</code></td><td align="left"><code class="filename">cxxabi_forced.h</code></td></tr></tbody></table></div></div><br class="table-break" /><p>
   And a large variety of extensions.
-</p><div class="table"><a id="table.ext_headers"></a><p class="title"><strong>Table 3.17. Extension Headers</strong></p><div class="table-contents"><table class="table" summary="Extension Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">ext/algorithm</code></td><td align="left"><code class="filename">ext/atomicity.h</code></td><td align="left"><code class="filename">ext/bitmap_allocator.h</code></td><td align="left"><code class="filename">ext/cast.h</code></td><td class="auto-generated"> </td></tr><tr><td align="left"><code class="filename">ext/codecvt_specializations.h</code></td><td align="left"><code class="filename">ext/concurrence.h</code></td><td align="left"><code class="filename">ext/debug_allocator.h</code></td><td align="left"><code class="filename">ext/enc_filebuf.h</code></td><td align="left"><code class="filename">ext/extptr_allocator.h</code></td></tr><tr><td align="left"><code class="filename">ext/functional</code></td><td align="left"><code class="filename">ext/iterator</code></td><td align="left"><code class="filename">ext/malloc_allocator.h</code></td><td align="left"><code class="filename">ext/memory</code></td><td align="left"><code class="filename">ext/mt_allocator.h</code></td></tr><tr><td align="left"><code class="filename">ext/new_allocator.h</code></td><td align="left"><code class="filename">ext/numeric</code></td><td align="left"><code class="filename">ext/numeric_traits.h</code></td><td align="left"><code class="filename">ext/pb_ds/assoc_container.h</code></td><td align="left"><code class="filename">ext/pb_ds/priority_queue.h</code></td></tr><tr><td align="left"><code class="filename">ext/pod_char_traits.h</code></td><td align="left"><code class="filename">ext/pool_allocator.h</code></td><td align="left"><code class="filename">ext/rb_tree</code></td><td align="left"><code class="filename">ext/rope</code></td><td align="left"><code class="filename">ext/slist</code></td></tr><tr><td align="left"><code class="filename">ext/stdio_filebuf.h</code></td><td align="left"><code class="filename">ext/stdio_sync_filebuf.h</code></td><td align="left"><code class="filename">ext/throw_allocator.h</code></td><td align="left"><code class="filename">ext/typelist.h</code></td><td align="left"><code class="filename">ext/type_traits.h</code></td></tr><tr><td align="left"><code class="filename">ext/vstring.h</code></td><td colspan="4" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p></p><div class="table"><a id="table.debug_headers"></a><p class="title"><strong>Table 3.18. Extension Debug Headers</strong></p><div class="table-contents"><table class="table" summary="Extension Debug Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">debug/array</code></td><td align="left"><code class="filename">debug/bitset</code></td><td align="left"><code class="filename">debug/deque</code></td><td align="left"><code class="filename">debug/forward_list</code></td><td align="left"><code class="filename">debug/list</code></td></tr><tr><td align="left"><code class="filename">debug/map</code></td><td align="left"><code class="filename">debug/set</code></td><td align="left"><code class="filename">debug/string</code></td><td align="left"><code class="filename">debug/unordered_map</code></td><td align="left"><code class="filename">debug/unordered_set</code></td></tr><tr><td align="left"><code class="filename">debug/vector</code></td><td colspan="4" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p></p><div class="table"><a id="table.parallel_headers"></a><p class="title"><strong>Table 3.19. Extension Parallel Headers</strong></p><div class="table-contents"><table class="table" summary="Extension Parallel Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /></colgroup><tbody><tr><td align="left"><code class="filename">parallel/algorithm</code></td><td align="left"><code class="filename">parallel/numeric</code></td></tr></tbody></table></div></div><br class="table-break" /></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="manual.intro.using.headers.mixing"></a>Mixing Headers</h3></div></div></div><p> A few simple rules.
+</p><div class="table"><a id="table.ext_headers"></a><p class="title"><strong>Table 3.20. Extension Headers</strong></p><div class="table-contents"><table class="table" summary="Extension Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">ext/algorithm</code></td><td align="left"><code class="filename">ext/atomicity.h</code></td><td align="left"><code class="filename">ext/bitmap_allocator.h</code></td><td align="left"><code class="filename">ext/cast.h</code></td><td class="auto-generated"> </td></tr><tr><td align="left"><code class="filename">ext/codecvt_specializations.h</code></td><td align="left"><code class="filename">ext/concurrence.h</code></td><td align="left"><code class="filename">ext/debug_allocator.h</code></td><td align="left"><code class="filename">ext/enc_filebuf.h</code></td><td align="left"><code class="filename">ext/extptr_allocator.h</code></td></tr><tr><td align="left"><code class="filename">ext/functional</code></td><td align="left"><code class="filename">ext/iterator</code></td><td align="left"><code class="filename">ext/malloc_allocator.h</code></td><td align="left"><code class="filename">ext/memory</code></td><td align="left"><code class="filename">ext/mt_allocator.h</code></td></tr><tr><td align="left"><code class="filename">ext/new_allocator.h</code></td><td align="left"><code class="filename">ext/numeric</code></td><td align="left"><code class="filename">ext/numeric_traits.h</code></td><td align="left"><code class="filename">ext/pb_ds/assoc_container.h</code></td><td align="left"><code class="filename">ext/pb_ds/priority_queue.h</code></td></tr><tr><td align="left"><code class="filename">ext/pod_char_traits.h</code></td><td align="left"><code class="filename">ext/pool_allocator.h</code></td><td align="left"><code class="filename">ext/rb_tree</code></td><td align="left"><code class="filename">ext/rope</code></td><td align="left"><code class="filename">ext/slist</code></td></tr><tr><td align="left"><code class="filename">ext/stdio_filebuf.h</code></td><td align="left"><code class="filename">ext/stdio_sync_filebuf.h</code></td><td align="left"><code class="filename">ext/throw_allocator.h</code></td><td align="left"><code class="filename">ext/typelist.h</code></td><td align="left"><code class="filename">ext/type_traits.h</code></td></tr><tr><td align="left"><code class="filename">ext/vstring.h</code></td><td colspan="4" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p></p><div class="table"><a id="table.debug_headers"></a><p class="title"><strong>Table 3.21. Extension Debug Headers</strong></p><div class="table-contents"><table class="table" summary="Extension Debug Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /><col align="left" class="c3" /><col align="left" class="c4" /><col align="left" class="c5" /></colgroup><tbody><tr><td align="left"><code class="filename">debug/array</code></td><td align="left"><code class="filename">debug/bitset</code></td><td align="left"><code class="filename">debug/deque</code></td><td align="left"><code class="filename">debug/forward_list</code></td><td align="left"><code class="filename">debug/list</code></td></tr><tr><td align="left"><code class="filename">debug/map</code></td><td align="left"><code class="filename">debug/set</code></td><td align="left"><code class="filename">debug/string</code></td><td align="left"><code class="filename">debug/unordered_map</code></td><td align="left"><code class="filename">debug/unordered_set</code></td></tr><tr><td align="left"><code class="filename">debug/vector</code></td><td colspan="4" align="left"> </td></tr></tbody></table></div></div><br class="table-break" /><p></p><div class="table"><a id="table.parallel_headers"></a><p class="title"><strong>Table 3.22. Extension Parallel Headers</strong></p><div class="table-contents"><table class="table" summary="Extension Parallel Headers" border="1"><colgroup><col align="left" class="c1" /><col align="left" class="c2" /></colgroup><tbody><tr><td align="left"><code class="filename">parallel/algorithm</code></td><td align="left"><code class="filename">parallel/numeric</code></td></tr></tbody></table></div></div><br class="table-break" /></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="manual.intro.using.headers.mixing"></a>Mixing Headers</h3></div></div></div><p> A few simple rules.
 </p><p>First, mixing different dialects of the standard headers is not
 possible. It's an all-or-nothing affair. Thus, code like
 </p><pre class="programlisting">