1# serial 13
2
3# Copyright (C) 2003, 2007, 2009-2020 Free Software Foundation, Inc.
4# This file is free software; the Free Software Foundation
5# gives unlimited permission to copy and/or distribute it,
6# with or without modifications, as long as this notice is preserved.
7
8# See if we have a working tzset function.
9# If so, arrange to compile the wrapper function.
10# For at least Solaris 2.5.1 and 2.6, this is necessary
11# because tzset can clobber the contents of the buffer
12# used by localtime.
13
14# Written by Paul Eggert and Jim Meyering.
15
16AC_DEFUN([gl_FUNC_TZSET],
17[
18  AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
19  AC_REQUIRE([gl_LOCALTIME_BUFFER_DEFAULTS])
20  AC_REQUIRE([AC_CANONICAL_HOST])
21  AC_CHECK_FUNCS_ONCE([tzset])
22  if test $ac_cv_func_tzset = no; then
23    HAVE_TZSET=0
24  fi
25  gl_FUNC_TZSET_CLOBBER
26  REPLACE_TZSET=0
27  case "$gl_cv_func_tzset_clobber" in
28    *yes)
29      REPLACE_TZSET=1
30      AC_DEFINE([TZSET_CLOBBERS_LOCALTIME], [1],
31        [Define if tzset clobbers localtime's static buffer.])
32      gl_LOCALTIME_BUFFER_NEEDED
33      ;;
34  esac
35  case "$host_os" in
36    mingw*) REPLACE_TZSET=1 ;;
37  esac
38])
39
40# Set gl_cv_func_tzset_clobber.
41AC_DEFUN([gl_FUNC_TZSET_CLOBBER],
42[
43  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
44  AC_CACHE_CHECK([whether tzset clobbers localtime buffer],
45                 [gl_cv_func_tzset_clobber],
46    [AC_RUN_IFELSE([AC_LANG_SOURCE([[
47#include <time.h>
48#include <stdlib.h>
49
50int
51main ()
52{
53  time_t t1 = 853958121;
54  struct tm *p, s;
55  putenv ("TZ=GMT0");
56  p = localtime (&t1);
57  s = *p;
58  putenv ("TZ=EST+3EDT+2,M10.1.0/00:00:00,M2.3.0/00:00:00");
59  tzset ();
60  return (p->tm_year != s.tm_year
61          || p->tm_mon != s.tm_mon
62          || p->tm_mday != s.tm_mday
63          || p->tm_hour != s.tm_hour
64          || p->tm_min != s.tm_min
65          || p->tm_sec != s.tm_sec);
66}
67  ]])],
68       [gl_cv_func_tzset_clobber=no],
69       [gl_cv_func_tzset_clobber=yes],
70       [case "$host_os" in
71                         # Guess all is fine on glibc systems.
72          *-gnu* | gnu*) gl_cv_func_tzset_clobber="guessing no" ;;
73                         # Guess all is fine on musl systems.
74          *-musl*)       gl_cv_func_tzset_clobber="guessing no" ;;
75                         # Guess no on native Windows.
76          mingw*)        gl_cv_func_tzset_clobber="guessing no" ;;
77                         # If we don't know, obey --enable-cross-guesses.
78          *)             gl_cv_func_tzset_clobber="$gl_cross_guess_inverted" ;;
79        esac
80       ])
81    ])
82
83  AC_DEFINE([HAVE_RUN_TZSET_TEST], [1],
84    [Define to 1 if you have run the test for working tzset.])
85])
86