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Diffstat (limited to 'm4/time_rz.m4')
| -rw-r--r-- | m4/time_rz.m4 | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/m4/time_rz.m4 b/m4/time_rz.m4 new file mode 100644 index 0000000..2dd64b2 --- /dev/null +++ b/m4/time_rz.m4 @@ -0,0 +1,53 @@ +dnl Time zone functions: tzalloc, localtime_rz, etc. + +dnl Copyright (C) 2015-2020 Free Software Foundation, Inc. +dnl This file is free software; the Free Software Foundation +dnl gives unlimited permission to copy and/or distribute it, +dnl with or without modifications, as long as this notice is preserved. + +dnl Written by Paul Eggert. + +AC_DEFUN([gl_TIME_RZ], +[ + AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) + AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS]) + AC_REQUIRE([AC_STRUCT_TIMEZONE]) + + # Mac OS X 10.6 loops forever with some time_t values. + # See Bug#27706, Bug#27736, and + # https://lists.gnu.org/r/bug-gnulib/2017-07/msg00142.html + AC_CACHE_CHECK([whether localtime loops forever near extrema], + [gl_cv_func_localtime_infloop_bug], + [gl_cv_func_localtime_infloop_bug=no + AC_RUN_IFELSE( + [AC_LANG_PROGRAM( + [[#include <stdlib.h> + #include <string.h> + #include <unistd.h> + #include <time.h> + ]], [[ + time_t t = -67768038400666600; + struct tm *tm; + char *tz = getenv ("TZ"); + if (! (tz && strcmp (tz, "QQQ0") == 0)) + return 0; + alarm (2); + tm = localtime (&t); + /* Use TM and *TM to suppress over-optimization. */ + return tm && tm->tm_isdst; + ]])], + [(TZ=QQQ0 ./conftest$EXEEXT) >/dev/null 2>&1 || + gl_cv_func_localtime_infloop_bug=yes], + [], + [gl_cv_func_localtime_infloop_bug="guessing no"])]) + if test "$gl_cv_func_localtime_infloop_bug" = yes; then + AC_DEFINE([HAVE_LOCALTIME_INFLOOP_BUG], 1, + [Define if localtime-like functions can loop forever on + extreme arguments.]) + fi + + AC_CHECK_TYPES([timezone_t], [], [], [[#include <time.h>]]) + if test "$ac_cv_type_timezone_t" = yes; then + HAVE_TIMEZONE_T=1 + fi +]) |