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emacs/m4/sys_time_h.m4
Paul Eggert 220a9ecba1 Merge from Gnulib
This incorporates:
2018-01-01 maint: Run 'make update-copyright'
2017-12-29 Add cross-compilation results for GNU/Hurd.
2017-12-12 explicit_bzero: port to macOS + Clang 9.0.0
2017-12-31 17:21:33 -08:00

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# Configure a replacement for <sys/time.h>.
# serial 9
# Copyright (C) 2007, 2009-2018 Free Software Foundation, Inc.
# This file is free software; the Free Software Foundation
# gives unlimited permission to copy and/or distribute it,
# with or without modifications, as long as this notice is preserved.
# Written by Paul Eggert and Martin Lambers.
AC_DEFUN([gl_HEADER_SYS_TIME_H],
[
dnl Use AC_REQUIRE here, so that the REPLACE_GETTIMEOFDAY=0 statement
dnl below is expanded once only, before all REPLACE_GETTIMEOFDAY=1
dnl statements that occur in other macros.
AC_REQUIRE([gl_HEADER_SYS_TIME_H_BODY])
])
AC_DEFUN([gl_HEADER_SYS_TIME_H_BODY],
[
AC_REQUIRE([AC_C_RESTRICT])
AC_REQUIRE([gl_HEADER_SYS_TIME_H_DEFAULTS])
AC_CHECK_HEADERS_ONCE([sys/time.h])
gl_CHECK_NEXT_HEADERS([sys/time.h])
if test $ac_cv_header_sys_time_h != yes; then
HAVE_SYS_TIME_H=0
fi
dnl On native Windows with MSVC, 'struct timeval' is defined in <winsock2.h>
dnl only. So include that header in the list.
gl_PREREQ_SYS_H_WINSOCK2
AC_CACHE_CHECK([for struct timeval], [gl_cv_sys_struct_timeval],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[#if HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#include <time.h>
#if HAVE_WINSOCK2_H
# include <winsock2.h>
#endif
]],
[[static struct timeval x; x.tv_sec = x.tv_usec;]])],
[gl_cv_sys_struct_timeval=yes],
[gl_cv_sys_struct_timeval=no])
])
if test $gl_cv_sys_struct_timeval != yes; then
HAVE_STRUCT_TIMEVAL=0
else
dnl On native Windows with a 64-bit 'time_t', 'struct timeval' is defined
dnl (in <sys/time.h> and <winsock2.h> for mingw64, in <winsock2.h> only
dnl for MSVC) with a tv_sec field of type 'long' (32-bit!), which is
dnl smaller than the 'time_t' type mandated by POSIX.
dnl On OpenBSD 5.1 amd64, tv_sec is 64 bits and time_t 32 bits, but
dnl that is good enough.
AC_CACHE_CHECK([for wide-enough struct timeval.tv_sec member],
[gl_cv_sys_struct_timeval_tv_sec],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[#if HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#include <time.h>
#if HAVE_WINSOCK2_H
# include <winsock2.h>
#endif
]],
[[static struct timeval x;
typedef int verify_tv_sec_type[
sizeof (time_t) <= sizeof x.tv_sec ? 1 : -1
];
]])],
[gl_cv_sys_struct_timeval_tv_sec=yes],
[gl_cv_sys_struct_timeval_tv_sec=no])
])
if test $gl_cv_sys_struct_timeval_tv_sec != yes; then
REPLACE_STRUCT_TIMEVAL=1
fi
fi
dnl Check for declarations of anything we want to poison if the
dnl corresponding gnulib module is not in use.
gl_WARN_ON_USE_PREPARE([[
#if HAVE_SYS_TIME_H
# include <sys/time.h>
#endif
#include <time.h>
]], [gettimeofday])
])
AC_DEFUN([gl_SYS_TIME_MODULE_INDICATOR],
[
dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
AC_REQUIRE([gl_HEADER_SYS_TIME_H_DEFAULTS])
gl_MODULE_INDICATOR_SET_VARIABLE([$1])
dnl Define it also as a C macro, for the benefit of the unit tests.
gl_MODULE_INDICATOR_FOR_TESTS([$1])
])
AC_DEFUN([gl_HEADER_SYS_TIME_H_DEFAULTS],
[
GNULIB_GETTIMEOFDAY=0; AC_SUBST([GNULIB_GETTIMEOFDAY])
dnl Assume POSIX behavior unless another module says otherwise.
HAVE_GETTIMEOFDAY=1; AC_SUBST([HAVE_GETTIMEOFDAY])
HAVE_STRUCT_TIMEVAL=1; AC_SUBST([HAVE_STRUCT_TIMEVAL])
HAVE_SYS_TIME_H=1; AC_SUBST([HAVE_SYS_TIME_H])
REPLACE_GETTIMEOFDAY=0; AC_SUBST([REPLACE_GETTIMEOFDAY])
REPLACE_STRUCT_TIMEVAL=0; AC_SUBST([REPLACE_STRUCT_TIMEVAL])
])