diff options
Diffstat (limited to 'libstdc++-v3/acinclude.m4')
| -rw-r--r-- | libstdc++-v3/acinclude.m4 | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4 index e668d2d..02fd349e 100644 --- a/libstdc++-v3/acinclude.m4 +++ b/libstdc++-v3/acinclude.m4 @@ -5745,6 +5745,41 @@ AC_DEFUN([GLIBCXX_ZONEINFO_DIR], [ ]) dnl +dnl Check for a tm_zone member in struct tm. +dnl +dnl This member is defined as const char* in Glibc, newlib, POSIX.1-2024, +dnl and as char* in BSD (including macOS). +dnl +dnl Defines: +dnl _GLIBCXX_USE_STRUCT_TM_TM_ZONE if struct tm has a tm_zone member. +dnl +AC_DEFUN([GLIBCXX_STRUCT_TM_TM_ZONE], [ + + AC_LANG_SAVE + AC_LANG_CPLUSPLUS + ac_save_CXXFLAGS="$CXXFLAGS" + CXXFLAGS="$CXXFLAGS -std=c++20" + + AC_CACHE_CHECK([for tm_zone member of struct tm], glibcxx_cv_tm_zone, [ + AC_COMPILE_IFELSE([AC_LANG_PROGRAM([#include <time.h> + ], + [struct tm t{}; t.tm_zone = (char*)0;] + )], + [glibcxx_cv_tm_zone=yes], + [glibcxx_cv_tm_zone=no] + ) + ]) + + if test $glibcxx_cv_tm_zone = yes; then + AC_DEFINE(_GLIBCXX_USE_STRUCT_TM_TM_ZONE, 1, + [Define if struct tm has a tm_zone member.]) + fi + + CXXFLAGS="$ac_save_CXXFLAGS" + AC_LANG_RESTORE +]) + +dnl dnl Check whether lock tables can be aligned to avoid false sharing. dnl dnl Defines: |