https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119918
--- Comment #2 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Tomasz Kaminski <tkami...@gcc.gnu.org>: https://gcc.gnu.org/g:74605294950e4a49627fb71fdedefea176f5ecf7 commit r16-137-g74605294950e4a49627fb71fdedefea176f5ecf7 Author: Tomasz KamiÅski <tkami...@redhat.com> Date: Thu Apr 24 09:32:24 2025 +0200 libstdc++: Constrain formatter for thread::id [PR119918] This patch add constraint __formatter::__char to _CharT type parameter of formatter<thread::id, _CharT> specialization, matching the constraint of formatting of integer/pointers that are used as native handles. The dependency on <format> header, is changed to <bits/formatfwd.h>. To achieve that, formatting of pointers is extracted from void const* specialization to internal __formatter_ptr<_CharT>, that can be forward declared. Finally, the handle representation is now printed directly to __fc.out(), by the formatter for handle type. To support this, internal formatters can now be constructed from _Spec object as alternative to invoking parse method. PR libstdc++/119918 libstdc++-v3/ChangeLog: * include/bits/formatfwd.h (__format::_Align): Moved from std/format. (std::__throw_format_error, __format::__formatter_str) (__format::__formatter_ptr): Declare. * include/std/format (__format::_Align): Moved to bits/formatfwd.h. (__formatter_int::__formatter_int): Define. (__format::__formatter_ptr): Extracted from formatter for const void*. (std::formatter<const void*, _CharT>, formatter<void*, _CharT>) (std::formatter<nullptr_t, _CharT>): Delegate to __formatter_ptr<_CharT>. * include/std/thread (std::formatter<thread::id, _CharT>): Constrain _CharT template parameter. (formatter<thread::id, _CharT>::parse): Specify default aligment, and qualify __throw_format_error to disable ADL. (formatter<thread::id, _CharT>::format): Use formatters to write directly to output. * testsuite/30_threads/thread/id/output.cc: Tests for formatting thread::id representing not-a-thread with padding and formattable concept. Reviewed-by: Jonathan Wakely <jwak...@redhat.com> Signed-off-by: Tomasz KamiÅski <tkami...@redhat.com>
