xref: /netbsd-src/external/gpl2/xcvs/dist/m4/tzset.m4 (revision a7c918477dd5f12c1da816ba05caf44eab2d06d6)
1#serial 2
2
3# Copyright (C) 2003 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_CLOBBER],
17[
18  AC_REQUIRE([AC_HEADER_TIME])
19  AC_CACHE_CHECK([whether tzset clobbers localtime buffer],
20                 gl_cv_func_tzset_clobber,
21  [
22  AC_RUN_IFELSE([AC_LANG_SOURCE([[
23#if TIME_WITH_SYS_TIME
24# include <sys/time.h>
25# include <time.h>
26#else
27# if HAVE_SYS_TIME_H
28#  include <sys/time.h>
29# else
30#  include <time.h>
31# endif
32#endif
33#include <stdlib.h>
34
35int
36main ()
37{
38  time_t t1 = 853958121;
39  struct tm *p, s;
40  putenv ("TZ=GMT0");
41  p = localtime (&t1);
42  s = *p;
43  putenv ("TZ=EST+3EDT+2,M10.1.0/00:00:00,M2.3.0/00:00:00");
44  tzset ();
45  exit (p->tm_year != s.tm_year
46        || p->tm_mon != s.tm_mon
47        || p->tm_mday != s.tm_mday
48        || p->tm_hour != s.tm_hour
49        || p->tm_min != s.tm_min
50        || p->tm_sec != s.tm_sec);
51}
52  ]])],
53       [gl_cv_func_tzset_clobber=no],
54       [gl_cv_func_tzset_clobber=yes],
55       [gl_cv_func_tzset_clobber=yes])])
56
57  AC_DEFINE(HAVE_RUN_TZSET_TEST, 1,
58    [Define to 1 if you have run the test for working tzset.])
59
60  if test $gl_cv_func_tzset_clobber = yes; then
61    gl_GETTIMEOFDAY_REPLACE_LOCALTIME
62
63    AC_DEFINE(tzset, rpl_tzset,
64      [Define to rpl_tzset if the wrapper function should be used.])
65    AC_DEFINE(TZSET_CLOBBERS_LOCALTIME_BUFFER, 1,
66      [Define if tzset clobbers localtime's static buffer.])
67  fi
68])
69