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# Copyright (C) 2001-2003, 2005, 2007, 2009-2017 Free Software Foundation, Inc.
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# This file is free software; the Free Software Foundation
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# gives unlimited permission to copy and/or distribute it,
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# with or without modifications, as long as this notice is preserved.
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AC_DEFUN([gl_FUNC_GETTIMEOFDAY],
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AC_REQUIRE([AC_C_RESTRICT])
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AC_REQUIRE([gl_HEADER_SYS_TIME_H])
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AC_REQUIRE([gl_HEADER_SYS_TIME_H_DEFAULTS])
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AC_CHECK_FUNCS_ONCE([gettimeofday])
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gl_gettimeofday_timezone=void
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if test $ac_cv_func_gettimeofday != yes; then
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gl_FUNC_GETTIMEOFDAY_CLOBBER
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AC_CACHE_CHECK([for gettimeofday with POSIX signature],
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[gl_cv_func_gettimeofday_posix_signature],
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[[#include <sys/time.h>
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int gettimeofday (struct timeval *restrict, void *restrict);
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[[/* glibc uses struct timezone * rather than the POSIX void *
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if _GNU_SOURCE is defined. However, since the only portable
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use of gettimeofday uses NULL as the second parameter, and
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since the glibc definition is actually more typesafe, it is
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not worth wrapping this to get a compliant signature. */
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int (*f) (struct timeval *restrict, void *restrict)
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return !(x | c.tv_sec | c.tv_usec);
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[gl_cv_func_gettimeofday_posix_signature=yes],
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[[#include <sys/time.h>
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int gettimeofday (struct timeval *restrict, struct timezone *restrict);
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[gl_cv_func_gettimeofday_posix_signature=almost],
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[gl_cv_func_gettimeofday_posix_signature=no])])])
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if test $gl_cv_func_gettimeofday_posix_signature = almost; then
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gl_gettimeofday_timezone='struct timezone'
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elif test $gl_cv_func_gettimeofday_posix_signature != yes; then
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REPLACE_GETTIMEOFDAY=1
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dnl If we override 'struct timeval', we also have to override gettimeofday.
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if test $REPLACE_STRUCT_TIMEVAL = 1; then
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REPLACE_GETTIMEOFDAY=1
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m4_ifdef([gl_FUNC_TZSET_CLOBBER], [
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case "$gl_cv_func_tzset_clobber" in
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REPLACE_GETTIMEOFDAY=1
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gl_GETTIMEOFDAY_REPLACE_LOCALTIME
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AC_DEFINE([tzset], [rpl_tzset],
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[Define to rpl_tzset if the wrapper function should be used.])
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AC_DEFINE([TZSET_CLOBBERS_LOCALTIME], [1],
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[Define if tzset clobbers localtime's static buffer.])
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AC_DEFINE_UNQUOTED([GETTIMEOFDAY_TIMEZONE], [$gl_gettimeofday_timezone],
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[Define this to 'void' or 'struct timezone' to match the system's
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declaration of the second argument to gettimeofday.])
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dnl See if gettimeofday clobbers the static buffer that localtime uses
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dnl for its return value. The gettimeofday function from Mac OS X 10.0.4
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dnl (i.e., Darwin 1.3.7) has this problem.
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dnl If it does, then arrange to use gettimeofday and localtime only via
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dnl the wrapper functions that work around the problem.
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AC_DEFUN([gl_FUNC_GETTIMEOFDAY_CLOBBER],
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AC_REQUIRE([gl_HEADER_SYS_TIME_H])
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AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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AC_CACHE_CHECK([whether gettimeofday clobbers localtime buffer],
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[gl_cv_func_gettimeofday_clobber],
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gettimeofday (&tv, NULL);
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return memcmp (lt, &saved_lt, sizeof (struct tm)) != 0;
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[gl_cv_func_gettimeofday_clobber=no],
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[gl_cv_func_gettimeofday_clobber=yes],
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[# When cross-compiling:
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# Guess all is fine on glibc systems.
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*-gnu*) gl_cv_func_gettimeofday_clobber="guessing no" ;;
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# If we don't know, assume the worst.
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*) gl_cv_func_gettimeofday_clobber="guessing yes" ;;
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case "$gl_cv_func_gettimeofday_clobber" in
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REPLACE_GETTIMEOFDAY=1
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gl_GETTIMEOFDAY_REPLACE_LOCALTIME
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AC_DEFINE([GETTIMEOFDAY_CLOBBERS_LOCALTIME], [1],
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[Define if gettimeofday clobbers the localtime buffer.])
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AC_DEFUN([gl_GETTIMEOFDAY_REPLACE_LOCALTIME], [
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# Prerequisites of lib/gettimeofday.c.
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AC_DEFUN([gl_PREREQ_GETTIMEOFDAY], [
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AC_CHECK_HEADERS([sys/timeb.h])
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AC_CHECK_FUNCS([_ftime])