1# serial 25
2dnl Copyright (C) 2002-2003, 2005-2007, 2009-2015 Free Software Foundation,
3dnl Inc.
4dnl This file is free software; the Free Software Foundation
5dnl gives unlimited permission to copy and/or distribute it,
6dnl with or without modifications, as long as this notice is preserved.
7
8dnl From Jim Meyering.
9
10AC_DEFUN([gl_FUNC_MKTIME],
11[
12  AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
13
14  dnl We don't use AC_FUNC_MKTIME any more, because it is no longer maintained
15  dnl in Autoconf and because it invokes AC_LIBOBJ.
16  AC_CHECK_HEADERS_ONCE([unistd.h])
17  AC_CHECK_DECLS_ONCE([alarm])
18  AC_REQUIRE([gl_MULTIARCH])
19  if test $APPLE_UNIVERSAL_BUILD = 1; then
20    # A universal build on Apple Mac OS X platforms.
21    # The test result would be 'yes' in 32-bit mode and 'no' in 64-bit mode.
22    # But we need a configuration result that is valid in both modes.
23    gl_cv_func_working_mktime=no
24  fi
25  AC_CACHE_CHECK([for working mktime], [gl_cv_func_working_mktime],
26    [AC_RUN_IFELSE(
27       [AC_LANG_SOURCE(
28[[/* Test program from Paul Eggert and Tony Leneis.  */
29#include <limits.h>
30#include <stdlib.h>
31#include <time.h>
32
33#ifdef HAVE_UNISTD_H
34# include <unistd.h>
35#endif
36
37#if HAVE_DECL_ALARM
38# include <signal.h>
39#endif
40
41/* Work around redefinition to rpl_putenv by other config tests.  */
42#undef putenv
43
44static time_t time_t_max;
45static time_t time_t_min;
46
47/* Values we'll use to set the TZ environment variable.  */
48static char *tz_strings[] = {
49  (char *) 0, "TZ=GMT0", "TZ=JST-9",
50  "TZ=EST+3EDT+2,M10.1.0/00:00:00,M2.3.0/00:00:00"
51};
52#define N_STRINGS (sizeof (tz_strings) / sizeof (tz_strings[0]))
53
54/* Return 0 if mktime fails to convert a date in the spring-forward gap.
55   Based on a problem report from Andreas Jaeger.  */
56static int
57spring_forward_gap ()
58{
59  /* glibc (up to about 1998-10-07) failed this test. */
60  struct tm tm;
61
62  /* Use the portable POSIX.1 specification "TZ=PST8PDT,M4.1.0,M10.5.0"
63     instead of "TZ=America/Vancouver" in order to detect the bug even
64     on systems that don't support the Olson extension, or don't have the
65     full zoneinfo tables installed.  */
66  putenv ("TZ=PST8PDT,M4.1.0,M10.5.0");
67
68  tm.tm_year = 98;
69  tm.tm_mon = 3;
70  tm.tm_mday = 5;
71  tm.tm_hour = 2;
72  tm.tm_min = 0;
73  tm.tm_sec = 0;
74  tm.tm_isdst = -1;
75  return mktime (&tm) != (time_t) -1;
76}
77
78static int
79mktime_test1 (time_t now)
80{
81  struct tm *lt;
82  return ! (lt = localtime (&now)) || mktime (lt) == now;
83}
84
85static int
86mktime_test (time_t now)
87{
88  return (mktime_test1 (now)
89          && mktime_test1 ((time_t) (time_t_max - now))
90          && mktime_test1 ((time_t) (time_t_min + now)));
91}
92
93static int
94irix_6_4_bug ()
95{
96  /* Based on code from Ariel Faigon.  */
97  struct tm tm;
98  tm.tm_year = 96;
99  tm.tm_mon = 3;
100  tm.tm_mday = 0;
101  tm.tm_hour = 0;
102  tm.tm_min = 0;
103  tm.tm_sec = 0;
104  tm.tm_isdst = -1;
105  mktime (&tm);
106  return tm.tm_mon == 2 && tm.tm_mday == 31;
107}
108
109static int
110bigtime_test (int j)
111{
112  struct tm tm;
113  time_t now;
114  tm.tm_year = tm.tm_mon = tm.tm_mday = tm.tm_hour = tm.tm_min = tm.tm_sec = j;
115  now = mktime (&tm);
116  if (now != (time_t) -1)
117    {
118      struct tm *lt = localtime (&now);
119      if (! (lt
120             && lt->tm_year == tm.tm_year
121             && lt->tm_mon == tm.tm_mon
122             && lt->tm_mday == tm.tm_mday
123             && lt->tm_hour == tm.tm_hour
124             && lt->tm_min == tm.tm_min
125             && lt->tm_sec == tm.tm_sec
126             && lt->tm_yday == tm.tm_yday
127             && lt->tm_wday == tm.tm_wday
128             && ((lt->tm_isdst < 0 ? -1 : 0 < lt->tm_isdst)
129                  == (tm.tm_isdst < 0 ? -1 : 0 < tm.tm_isdst))))
130        return 0;
131    }
132  return 1;
133}
134
135static int
136year_2050_test ()
137{
138  /* The correct answer for 2050-02-01 00:00:00 in Pacific time,
139     ignoring leap seconds.  */
140  unsigned long int answer = 2527315200UL;
141
142  struct tm tm;
143  time_t t;
144  tm.tm_year = 2050 - 1900;
145  tm.tm_mon = 2 - 1;
146  tm.tm_mday = 1;
147  tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
148  tm.tm_isdst = -1;
149
150  /* Use the portable POSIX.1 specification "TZ=PST8PDT,M4.1.0,M10.5.0"
151     instead of "TZ=America/Vancouver" in order to detect the bug even
152     on systems that don't support the Olson extension, or don't have the
153     full zoneinfo tables installed.  */
154  putenv ("TZ=PST8PDT,M4.1.0,M10.5.0");
155
156  t = mktime (&tm);
157
158  /* Check that the result is either a failure, or close enough
159     to the correct answer that we can assume the discrepancy is
160     due to leap seconds.  */
161  return (t == (time_t) -1
162          || (0 < t && answer - 120 <= t && t <= answer + 120));
163}
164
165int
166main ()
167{
168  int result = 0;
169  time_t t, delta;
170  int i, j;
171  int time_t_signed_magnitude = (time_t) ~ (time_t) 0 < (time_t) -1;
172  int time_t_signed = ! ((time_t) 0 < (time_t) -1);
173
174#if HAVE_DECL_ALARM
175  /* This test makes some buggy mktime implementations loop.
176     Give up after 60 seconds; a mktime slower than that
177     isn't worth using anyway.  */
178  signal (SIGALRM, SIG_DFL);
179  alarm (60);
180#endif
181
182  time_t_max = (! time_t_signed
183                ? (time_t) -1
184                : ((((time_t) 1 << (sizeof (time_t) * CHAR_BIT - 2)) - 1)
185                   * 2 + 1));
186  time_t_min = (! time_t_signed
187                ? (time_t) 0
188                : time_t_signed_magnitude
189                ? ~ (time_t) 0
190                : ~ time_t_max);
191
192  delta = time_t_max / 997; /* a suitable prime number */
193  for (i = 0; i < N_STRINGS; i++)
194    {
195      if (tz_strings[i])
196        putenv (tz_strings[i]);
197
198      for (t = 0; t <= time_t_max - delta && (result & 1) == 0; t += delta)
199        if (! mktime_test (t))
200          result |= 1;
201      if ((result & 2) == 0
202          && ! (mktime_test ((time_t) 1)
203                && mktime_test ((time_t) (60 * 60))
204                && mktime_test ((time_t) (60 * 60 * 24))))
205        result |= 2;
206
207      for (j = 1; (result & 4) == 0; j <<= 1)
208        {
209          if (! bigtime_test (j))
210            result |= 4;
211          if (INT_MAX / 2 < j)
212            break;
213        }
214      if ((result & 8) == 0 && ! bigtime_test (INT_MAX))
215        result |= 8;
216    }
217  if (! irix_6_4_bug ())
218    result |= 16;
219  if (! spring_forward_gap ())
220    result |= 32;
221  if (! year_2050_test ())
222    result |= 64;
223  return result;
224}]])],
225       [gl_cv_func_working_mktime=yes],
226       [gl_cv_func_working_mktime=no],
227       [gl_cv_func_working_mktime=no])
228    ])
229
230  if test $gl_cv_func_working_mktime = no; then
231    REPLACE_MKTIME=1
232  else
233    REPLACE_MKTIME=0
234  fi
235])
236
237AC_DEFUN([gl_FUNC_MKTIME_INTERNAL], [
238  AC_REQUIRE([gl_FUNC_MKTIME])
239  if test $REPLACE_MKTIME = 0; then
240    dnl BeOS has __mktime_internal in libc, but other platforms don't.
241    AC_CHECK_FUNC([__mktime_internal],
242      [AC_DEFINE([mktime_internal], [__mktime_internal],
243         [Define to the real name of the mktime_internal function.])
244      ],
245      [dnl mktime works but it doesn't export __mktime_internal,
246       dnl so we need to substitute our own mktime implementation.
247       REPLACE_MKTIME=1
248      ])
249  fi
250])
251
252# Prerequisites of lib/mktime.c.
253AC_DEFUN([gl_PREREQ_MKTIME], [:])
254