https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111632
Bug ID: 111632 Summary: gcc's C++ components fail to compile against recent libc++ headers Product: gcc Version: 14.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: other Assignee: unassigned at gcc dot gnu.org Reporter: dimitry at andric dot com Target Milestone: --- As reported in https://bugs.freebsd.org/274041 and a number of related PRs, when building gcc's C++ sources against recent libc++ (>= 17), the poisoning of the ctype macros due to including safe-ctype.h before including C++ standard headers such as <list>, <map>, etc, causes many compilation errors, similar to: In file included from /home/dim/src/gcc/master/gcc/gensupport.cc:23: In file included from /home/dim/src/gcc/master/gcc/system.h:233: In file included from /usr/include/c++/v1/vector:321: In file included from /usr/include/c++/v1/__format/formatter_bool.h:20: In file included from /usr/include/c++/v1/__format/formatter_integral.h:32: In file included from /usr/include/c++/v1/locale:202: /usr/include/c++/v1/__locale:546:5: error: '__abi_tag__' attribute only applies to structs, variables, functions, and namespaces 546 | _LIBCPP_INLINE_VISIBILITY | ^ /usr/include/c++/v1/__config:813:37: note: expanded from macro '_LIBCPP_INLINE_VISIBILITY' 813 | # define _LIBCPP_INLINE_VISIBILITY _LIBCPP_HIDE_FROM_ABI | ^ /usr/include/c++/v1/__config:792:26: note: expanded from macro '_LIBCPP_HIDE_FROM_ABI' 792 | __attribute__((__abi_tag__(_LIBCPP_TOSTRING(_LIBCPP_VERSIONED_IDENTIFIER)))) | ^ In file included from /home/dim/src/gcc/master/gcc/gensupport.cc:23: In file included from /home/dim/src/gcc/master/gcc/system.h:233: In file included from /usr/include/c++/v1/vector:321: In file included from /usr/include/c++/v1/__format/formatter_bool.h:20: In file included from /usr/include/c++/v1/__format/formatter_integral.h:32: In file included from /usr/include/c++/v1/locale:202: /usr/include/c++/v1/__locale:547:37: error: expected ';' at end of declaration list 547 | char_type toupper(char_type __c) const | ^ /usr/include/c++/v1/__locale:553:48: error: too many arguments provided to function-like macro invocation 553 | const char_type* toupper(char_type* __low, const char_type* __high) const | ^ /home/dim/src/gcc/master/gcc/../include/safe-ctype.h:146:9: note: macro 'toupper' defined here 146 | #define toupper(c) do_not_use_toupper_with_safe_ctype | ^ This is because libc++ uses different transitive includes than libstdc++, and some of those transitive includes pull in various ctype declarations (typically via <locale>). There was already a special case for including <string> before safe-ctype.h, so move the rest of the C++ standard header includes to the same location, to fix the problem.