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| author | Jonathan Wakely <jwakely@redhat.com> | 2024-03-07 12:00:55 +0000 |
|---|---|---|
| committer | Jonathan Wakely <jwakely@redhat.com> | 2024-03-13 21:25:13 +0000 |
| commit | d6490157b3e7ec45a024d1a2acc96e53934dbb0e (patch) | |
| tree | d8e0211a0eae7dcc5ac88e16043e6fe62d29981d | |
| parent | 11caf47b599568c6c6f5a12cf8e21f50778176d3 (diff) | |
| download | gcc-d6490157b3e7ec45a024d1a2acc96e53934dbb0e.zip gcc-d6490157b3e7ec45a024d1a2acc96e53934dbb0e.tar.gz gcc-d6490157b3e7ec45a024d1a2acc96e53934dbb0e.tar.bz2 | |
libstdc++: Document that _GLIBCXX_CONCEPT_CHECKS might be removed in future
The macro-based concept checks are unmaintained and do not support C++11
or later, so reject valid code. If nobody plans to update them we should
consider removing them. Alternatively, we could ignore the macro for
C++11 and later, so they have no effect and don't reject valid code.
libstdc++-v3/ChangeLog:
* doc/xml/manual/debug.xml: Document that concept checking might
be removed in future.
* doc/xml/manual/extensions.xml: Likewise.
| -rw-r--r-- | libstdc++-v3/doc/xml/manual/debug.xml | 2 | ||||
| -rw-r--r-- | libstdc++-v3/doc/xml/manual/extensions.xml | 18 |
2 files changed, 14 insertions, 6 deletions
diff --git a/libstdc++-v3/doc/xml/manual/debug.xml b/libstdc++-v3/doc/xml/manual/debug.xml index 42d4d32..7f6d087 100644 --- a/libstdc++-v3/doc/xml/manual/debug.xml +++ b/libstdc++-v3/doc/xml/manual/debug.xml @@ -351,6 +351,8 @@ <para> The <link linkend="manual.ext.compile_checks">Compile-Time Checks</link> extension has compile-time checks for many algorithms. + These checks were designed for C++98 and have not been updated to work + with C++11 and later standards. They might be removed at a future date. </para> </section> diff --git a/libstdc++-v3/doc/xml/manual/extensions.xml b/libstdc++-v3/doc/xml/manual/extensions.xml index d4fe2f5..490a50c 100644 --- a/libstdc++-v3/doc/xml/manual/extensions.xml +++ b/libstdc++-v3/doc/xml/manual/extensions.xml @@ -77,8 +77,7 @@ extensions, be aware of two things: object file. The checks are also cleaner and easier to read and understand. </para> - <para>They are off by default for all versions of GCC from 3.0 to 3.4 (the - latest release at the time of writing). + <para>They are off by default for all GCC 3.0 and all later versions. They can be enabled at configure time with <link linkend="manual.intro.setup.configure"><literal>--enable-concept-checks</literal></link>. You can enable them on a per-translation-unit basis with @@ -89,10 +88,17 @@ extensions, be aware of two things: </para> <para>Please note that the concept checks only validate the requirements - of the old C++03 standard. C++11 was expected to have first-class - support for template parameter constraints based on concepts in the core - language. This would have obviated the need for the library-simulated concept - checking described above, but was not part of C++11. + of the old C++03 standard and reject some valid code that meets the relaxed + requirements of C++11 and later standards. + C++11 was expected to have first-class support for template parameter + constraints based on concepts in the core language. + This would have obviated the need for the library-simulated concept checking + described above, but was not part of C++11. + C++20 adds a different model of concepts, which is now used to constrain + some new parts of the C++20 library, e.g. the + <filename><ranges></filename> header and the new overloads in the + <filename><algorithm></filename> header for working with ranges. + The old library-simulated concept checks might be removed at a future date. </para> </chapter> |