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# mktime.m4
# serial 39
dnl Copyright (C) 2002-2003, 2005-2007, 2009-2024 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 From Jim Meyering.
AC_DEFUN([gl_TIME_T_IS_SIGNED],
[
AC_CACHE_CHECK([whether time_t is signed],
[gl_cv_time_t_is_signed],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM([[#include <time.h>
char time_t_signed[(time_t) -1 < 0 ? 1 : -1];]])],
[gl_cv_time_t_is_signed=yes],
[gl_cv_time_t_is_signed=no])])
if test $gl_cv_time_t_is_signed = yes; then
AC_DEFINE([TIME_T_IS_SIGNED], [1], [Define to 1 if time_t is signed.])
fi
])
dnl Test whether mktime works. Set gl_cv_func_working_mktime.
AC_DEFUN([gl_FUNC_MKTIME_WORKS],
[
AC_REQUIRE([gl_TIME_T_IS_SIGNED])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
dnl We don't use AC_FUNC_MKTIME any more, because it is no longer maintained
dnl in Autoconf and because it invokes AC_LIBOBJ.
AC_CHECK_HEADERS_ONCE([unistd.h])
AC_CHECK_DECLS_ONCE([alarm])
AC_REQUIRE([gl_MULTIARCH])
AC_CACHE_CHECK([for working mktime], [gl_cv_func_working_mktime],
[if test $APPLE_UNIVERSAL_BUILD = 1; then
# A universal build on Apple Mac OS X platforms.
# The test result would be 'yes' in 32-bit mode and 'no' in 64-bit mode.
# But we need a configuration result that is valid in both modes.
gl_cv_func_working_mktime="guessing no"
else
AC_RUN_IFELSE(
[AC_LANG_SOURCE(
[[/* Test program from Paul Eggert and Tony Leneis. */
#include <limits.h>
#include <stdlib.h>
#include <time.h>
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#if HAVE_DECL_ALARM
# include <signal.h>
#endif
]GL_MDA_DEFINES[
#ifndef TIME_T_IS_SIGNED
# define TIME_T_IS_SIGNED 0
#endif
static time_t time_t_max;
static time_t time_t_min;
/* Values we'll use to set the TZ environment variable. */
static char *tz_strings[] = {
(char *) 0, "TZ=GMT0", "TZ=JST-9",
"TZ=EST+3EDT+2,M10.1.0/00:00:00,M2.3.0/00:00:00"
};
#define N_STRINGS (sizeof (tz_strings) / sizeof (tz_strings[0]))
/* Return 0 if mktime fails to convert a date in the spring-forward gap.
Based on a problem report from Andreas Jaeger. */
static int
spring_forward_gap ()
{
/* glibc (up to about 1998-10-07) failed this test. */
struct tm tm;
/* Use the portable POSIX.1 specification "TZ=PST8PDT,M4.1.0,M10.5.0"
instead of "TZ=America/Vancouver" in order to detect the bug even
on systems that don't support the Olson extension, or don't have the
full zoneinfo tables installed. */
if (putenv ("TZ=PST8PDT,M4.1.0,M10.5.0") != 0)
return -1;
tm.tm_year = 98;
tm.tm_mon = 3;
tm.tm_mday = 5;
tm.tm_hour = 2;
tm.tm_min = 0;
tm.tm_sec = 0;
tm.tm_isdst = -1;
return mktime (&tm) != (time_t) -1;
}
static int
mktime_test1 (time_t now)
{
struct tm *lt;
return ! (lt = localtime (&now)) || mktime (lt) == now;
}
static int
mktime_test (time_t now)
{
return (mktime_test1 (now)
&& mktime_test1 ((time_t) (time_t_max - now))
&& mktime_test1 ((time_t) (time_t_min + now)));
}
static int
irix_6_4_bug ()
{
/* Based on code from Ariel Faigon. */
struct tm tm;
tm.tm_year = 96;
tm.tm_mon = 3;
tm.tm_mday = 0;
tm.tm_hour = 0;
tm.tm_min = 0;
tm.tm_sec = 0;
tm.tm_isdst = -1;
mktime (&tm);
return tm.tm_mon == 2 && tm.tm_mday == 31;
}
static int
bigtime_test (int j)
{
struct tm tm;
time_t now;
tm.tm_year = tm.tm_mon = tm.tm_mday = tm.tm_hour = tm.tm_min = tm.tm_sec = j;
now = mktime (&tm);
if (now != (time_t) -1)
{
struct tm *lt = localtime (&now);
if (! (lt
&& lt->tm_year == tm.tm_year
&& lt->tm_mon == tm.tm_mon
&& lt->tm_mday == tm.tm_mday
&& lt->tm_hour == tm.tm_hour
&& lt->tm_min == tm.tm_min
&& lt->tm_sec == tm.tm_sec
&& lt->tm_yday == tm.tm_yday
&& lt->tm_wday == tm.tm_wday
&& ((lt->tm_isdst < 0 ? -1 : 0 < lt->tm_isdst)
== (tm.tm_isdst < 0 ? -1 : 0 < tm.tm_isdst))))
return 0;
}
return 1;
}
static int
year_2050_test ()
{
/* The correct answer for 2050-02-01 00:00:00 in Pacific time,
ignoring leap seconds. */
unsigned long int answer = 2527315200UL;
struct tm tm;
time_t t;
tm.tm_year = 2050 - 1900;
tm.tm_mon = 2 - 1;
tm.tm_mday = 1;
tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
tm.tm_isdst = -1;
/* Use the portable POSIX.1 specification "TZ=PST8PDT,M4.1.0,M10.5.0"
instead of "TZ=America/Vancouver" in order to detect the bug even
on systems that don't support the Olson extension, or don't have the
full zoneinfo tables installed. */
if (putenv ("TZ=PST8PDT,M4.1.0,M10.5.0") != 0)
return -1;
t = mktime (&tm);
/* Check that the result is either a failure, or close enough
to the correct answer that we can assume the discrepancy is
due to leap seconds. */
return (t == (time_t) -1
|| (0 < t && answer - 120 <= t && t <= answer + 120));
}
static int
indiana_test ()
{
if (putenv ("TZ=America/Indiana/Indianapolis") != 0)
return -1;
struct tm tm;
tm.tm_year = 1986 - 1900; tm.tm_mon = 4 - 1; tm.tm_mday = 28;
tm.tm_hour = 16; tm.tm_min = 24; tm.tm_sec = 50; tm.tm_isdst = 0;
time_t std = mktime (&tm);
if (! (std == 515107490 || std == 515107503))
return 1;
/* This platform supports TZDB, either without or with leap seconds.
Return true if GNU Bug#48085 is absent. */
tm.tm_isdst = 1;
time_t dst = mktime (&tm);
return std - dst == 60 * 60;
}
int
main ()
{
int result = 0;
time_t t, delta;
int i, j;
int time_t_signed_magnitude = (time_t) ~ (time_t) 0 < (time_t) -1;
#if HAVE_DECL_ALARM
/* This test makes some buggy mktime implementations loop.
Give up after 60 seconds; a mktime slower than that
isn't worth using anyway. */
signal (SIGALRM, SIG_DFL);
alarm (60);
#endif
time_t_max = (! TIME_T_IS_SIGNED
? (time_t) -1
: ((((time_t) 1 << (sizeof (time_t) * CHAR_BIT - 2)) - 1)
* 2 + 1));
time_t_min = (! TIME_T_IS_SIGNED
? (time_t) 0
: time_t_signed_magnitude
? ~ (time_t) 0
: ~ time_t_max);
delta = time_t_max / 997; /* a suitable prime number */
for (i = 0; i < N_STRINGS; i++)
{
if (tz_strings[i])
putenv (tz_strings[i]);
for (t = 0; t <= time_t_max - delta && (result & 1) == 0; t += delta)
if (! mktime_test (t))
result |= 1;
if ((result & 2) == 0
&& ! (mktime_test ((time_t) 1)
&& mktime_test ((time_t) (60 * 60))
&& mktime_test ((time_t) (60 * 60 * 24))))
result |= 2;
for (j = 1; (result & 4) == 0; j <<= 1)
{
if (! bigtime_test (j))
result |= 4;
if (INT_MAX / 2 < j)
break;
}
if ((result & 8) == 0 && ! bigtime_test (INT_MAX))
result |= 8;
}
if (! irix_6_4_bug ())
result |= 16;
if (! spring_forward_gap ())
result |= 32;
if (! year_2050_test () || ! indiana_test ())
result |= 64;
return result;
}]])],
[gl_cv_func_working_mktime=yes],
[gl_cv_func_working_mktime=no],
[case "$host_os" in
# Guess no on native Windows.
mingw* | windows*) gl_cv_func_working_mktime="guessing no" ;;
*) gl_cv_func_working_mktime="$gl_cross_guess_normal" ;;
esac
])
fi
])
])
dnl Main macro of module 'mktime'.
AC_DEFUN([gl_FUNC_MKTIME],
[
AC_REQUIRE([gl_TIME_H_DEFAULTS])
AC_REQUIRE([AC_CANONICAL_HOST])
AC_REQUIRE([gl_FUNC_MKTIME_WORKS])
if test "$gl_cv_func_working_mktime" != yes; then
REPLACE_MKTIME=1
AC_DEFINE([NEED_MKTIME_WORKING], [1],
[Define if the compilation of mktime.c should define 'mktime'
with the algorithmic workarounds.])
fi
case "$host_os" in
mingw* | windows*)
REPLACE_MKTIME=1
AC_DEFINE([NEED_MKTIME_WINDOWS], [1],
[Define if the compilation of mktime.c should define 'mktime'
with the native Windows TZ workaround.])
;;
esac
])
dnl Main macro of module 'mktime-internal'.
AC_DEFUN([gl_FUNC_MKTIME_INTERNAL], [
AC_REQUIRE([gl_FUNC_MKTIME_WORKS])
WANT_MKTIME_INTERNAL=0
dnl BeOS has __mktime_internal in libc, but other platforms don't.
AC_CHECK_FUNC([__mktime_internal],
[AC_DEFINE([mktime_internal], [__mktime_internal],
[Define to the real name of the mktime_internal function.])
],
[dnl mktime works but it doesn't export __mktime_internal,
dnl so we need to substitute our own mktime implementation.
WANT_MKTIME_INTERNAL=1
AC_DEFINE([NEED_MKTIME_INTERNAL], [1],
[Define if the compilation of mktime.c should define 'mktime_internal'.])
])
])
# Prerequisites of lib/mktime.c.
AC_DEFUN([gl_PREREQ_MKTIME], [:])
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