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emacs/m4/time_r.m4
Paul Eggert 035f5aaa91 Merge from gnulib, incorporating:
2015-01-01 version-etc: new year
2015-01-01 11:06:53 -08:00

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dnl Reentrant time functions: localtime_r, gmtime_r.
dnl Copyright (C) 2003, 2006-2015 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 Written by Paul Eggert.
AC_DEFUN([gl_TIME_R],
[
dnl Persuade glibc and Solaris <time.h> to declare localtime_r.
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS])
AC_REQUIRE([AC_C_RESTRICT])
dnl Some systems don't declare localtime_r() and gmtime_r() if _REENTRANT is
dnl not defined.
AC_CHECK_DECLS([localtime_r], [], [], [[#include <time.h>]])
if test $ac_cv_have_decl_localtime_r = no; then
HAVE_DECL_LOCALTIME_R=0
fi
AC_CHECK_FUNCS_ONCE([localtime_r])
if test $ac_cv_func_localtime_r = yes; then
HAVE_LOCALTIME_R=1
AC_CACHE_CHECK([whether localtime_r is compatible with its POSIX signature],
[gl_cv_time_r_posix],
[AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[#include <time.h>]],
[[/* We don't need to append 'restrict's to the argument types,
even though the POSIX signature has the 'restrict's,
since C99 says they can't affect type compatibility. */
struct tm * (*ptr) (time_t const *, struct tm *) = localtime_r;
if (ptr) return 0;
/* Check the return type is a pointer.
On HP-UX 10 it is 'int'. */
*localtime_r (0, 0);]])
],
[gl_cv_time_r_posix=yes],
[gl_cv_time_r_posix=no])
])
if test $gl_cv_time_r_posix = yes; then
REPLACE_LOCALTIME_R=0
else
REPLACE_LOCALTIME_R=1
fi
else
HAVE_LOCALTIME_R=0
fi
])
# Prerequisites of lib/time_r.c.
AC_DEFUN([gl_PREREQ_TIME_R], [
:
])