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54 lines
1.8 KiB
Plaintext
54 lines
1.8 KiB
Plaintext
dnl Time zone functions: tzalloc, localtime_rz, etc.
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dnl Copyright (C) 2015-2021 Free Software Foundation, Inc.
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dnl This file is free software; the Free Software Foundation
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dnl gives unlimited permission to copy and/or distribute it,
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dnl with or without modifications, as long as this notice is preserved.
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dnl Written by Paul Eggert.
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AC_DEFUN([gl_TIME_RZ],
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[
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AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
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AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
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AC_REQUIRE([AC_STRUCT_TIMEZONE])
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# On Mac OS X 10.6, localtime loops forever with some time_t values.
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# See Bug#27706, Bug#27736, and
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# https://lists.gnu.org/r/bug-gnulib/2017-07/msg00142.html
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AC_CACHE_CHECK([whether localtime works even near extrema],
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[gl_cv_func_localtime_works],
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[gl_cv_func_localtime_works=yes
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AC_RUN_IFELSE(
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[AC_LANG_PROGRAM(
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[[#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <time.h>
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]], [[
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time_t t = -67768038400666600;
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struct tm *tm;
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char *tz = getenv ("TZ");
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if (! (tz && strcmp (tz, "QQQ0") == 0))
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return 0;
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alarm (2);
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tm = localtime (&t);
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/* Use TM and *TM to suppress over-optimization. */
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return tm && tm->tm_isdst;
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]])],
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[(TZ=QQQ0 ./conftest$EXEEXT) >/dev/null 2>&1 ||
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gl_cv_func_localtime_works=no],
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[],
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[gl_cv_func_localtime_works="guessing yes"])])
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if test "$gl_cv_func_localtime_works" = no; then
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AC_DEFINE([HAVE_LOCALTIME_INFLOOP_BUG], 1,
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[Define if localtime-like functions can loop forever on
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extreme arguments.])
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fi
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AC_CHECK_TYPES([timezone_t], [], [], [[#include <time.h>]])
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if test "$ac_cv_type_timezone_t" = yes; then
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HAVE_TIMEZONE_T=1
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fi
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])
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