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Diffstat (limited to 'm4/mktime.m4')
| -rw-r--r-- | m4/mktime.m4 | 299 |
1 files changed, 299 insertions, 0 deletions
diff --git a/m4/mktime.m4 b/m4/mktime.m4 new file mode 100644 index 0000000..4b3e399 --- /dev/null +++ b/m4/mktime.m4 @@ -0,0 +1,299 @@ +# serial 30 +dnl Copyright (C) 2002-2003, 2005-2007, 2009-2018 Free Software Foundation, +dnl 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+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles + + dnl We don't use AC_FUNC_MKTIME any more, because it is no longer maintained + dnl in Autoconf and because it invokes AC_LIBOBJ.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_CHECK_FUNCS_ONCE([tzset]) + AC_REQUIRE([gl_MULTIARCH]) + 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=no + fi + AC_CACHE_CHECK([for working mktime], [gl_cv_func_working_mktime], + [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 + +#ifndef TIME_T_IS_SIGNED +# define TIME_T_IS_SIGNED 0 +#endif + +/* Work around redefinition to rpl_putenv by other config tests. */ +#undef putenv + +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. */ + putenv ("TZ=PST8PDT,M4.1.0,M10.5.0"); + + 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. */ + putenv ("TZ=PST8PDT,M4.1.0,M10.5.0"); + + 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)); +} + +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 ()) + 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*) gl_cv_func_working_mktime="guessing no" ;; + *) gl_cv_func_working_mktime="guessing no" ;; + esac + ]) + ]) +]) + +dnl Main macro of module 'mktime'. +AC_DEFUN([gl_FUNC_MKTIME], +[ + AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS]) + AC_REQUIRE([AC_CANONICAL_HOST]) + AC_REQUIRE([gl_FUNC_MKTIME_WORKS]) + + REPLACE_MKTIME=0 + 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*) + 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], [:]) |