1#serial 7
2
3# Copyright (C) 2001, 2002, 2003, 2005 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
8dnl From Jim Meyering.
9dnl
10dnl See if gettimeofday clobbers the static buffer that localtime uses
11dnl for its return value.  The gettimeofday function from Mac OS X 10.0.4
12dnl (i.e., Darwin 1.3.7) has this problem.
13dnl
14dnl If it does, then arrange to use gettimeofday and localtime only via
15dnl the wrapper functions that work around the problem.
16
17AC_DEFUN([AC_FUNC_GETTIMEOFDAY_CLOBBER],
18[
19 AC_REQUIRE([AC_HEADER_TIME])
20 AC_CACHE_CHECK([whether gettimeofday clobbers localtime buffer],
21  jm_cv_func_gettimeofday_clobber,
22  [AC_TRY_RUN([
23#include <stdio.h>
24#include <string.h>
25
26#if TIME_WITH_SYS_TIME
27# include <sys/time.h>
28# include <time.h>
29#else
30# if HAVE_SYS_TIME_H
31#  include <sys/time.h>
32# else
33#  include <time.h>
34# endif
35#endif
36
37#include <stdlib.h>
38
39int
40main ()
41{
42  time_t t = 0;
43  struct tm *lt;
44  struct tm saved_lt;
45  struct timeval tv;
46  lt = localtime (&t);
47  saved_lt = *lt;
48  gettimeofday (&tv, NULL);
49  if (memcmp (lt, &saved_lt, sizeof (struct tm)) != 0)
50    exit (1);
51
52  exit (0);
53}
54	  ],
55	 jm_cv_func_gettimeofday_clobber=no,
56	 jm_cv_func_gettimeofday_clobber=yes,
57	 dnl When crosscompiling, assume it is broken.
58	 jm_cv_func_gettimeofday_clobber=yes)
59  ])
60  if test $jm_cv_func_gettimeofday_clobber = yes; then
61    gl_GETTIMEOFDAY_REPLACE_LOCALTIME
62
63    AC_DEFINE(gettimeofday, rpl_gettimeofday,
64      [Define to rpl_gettimeofday if the replacement function should be used.])
65    gl_PREREQ_GETTIMEOFDAY
66  fi
67])
68
69AC_DEFUN([gl_GETTIMEOFDAY_REPLACE_LOCALTIME], [
70  AC_LIBOBJ(gettimeofday)
71  AC_DEFINE(gmtime, rpl_gmtime,
72    [Define to rpl_gmtime if the replacement function should be used.])
73  AC_DEFINE(localtime, rpl_localtime,
74    [Define to rpl_localtime if the replacement function should be used.])
75])
76
77# Prerequisites of lib/gettimeofday.c.
78AC_DEFUN([gl_PREREQ_GETTIMEOFDAY], [
79  AC_REQUIRE([AC_HEADER_TIME])
80])
81