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# serial 3
# See if we need to provide utimensat replacement.
dnl Copyright (C) 2009, 2010 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.
# Written by Eric Blake.
AC_DEFUN([gl_FUNC_UTIMENSAT],
[
AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
AC_CHECK_FUNCS_ONCE([utimensat])
if test $ac_cv_func_utimensat = no; then
HAVE_UTIMENSAT=0
AC_LIBOBJ([utimensat])
else
AC_CACHE_CHECK([whether utimensat works],
[gl_cv_func_utimensat_works],
[AC_RUN_IFELSE([AC_LANG_PROGRAM([[
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
]], [[struct timespec ts[2] = { { 1, UTIME_OMIT }, { 1, UTIME_NOW } };
struct stat st;
const char *f = "conftest.file";
if (close (creat (f, 0600))) return 1;
if (utimensat (AT_FDCWD, f, NULL, AT_SYMLINK_NOFOLLOW)) return 2;
if (utimensat (AT_FDCWD, f, ts, 0)) return 3;
sleep (1);
ts[0].tv_nsec = UTIME_NOW;
ts[1].tv_nsec = UTIME_OMIT;
if (utimensat (AT_FDCWD, f, ts, 0)) return 4;
if (stat (f, &st)) return 5;
if (st.st_ctime < st.st_atime) return 6;]])],
dnl FIXME: simplify this in 2012, when file system bugs are no longer common
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
#ifdef __linux__
/* The Linux kernel added utimensat in 2.6.22, but has bugs with UTIME_OMIT
in several file systems as recently as 2.6.32. Always replace utimensat
to support older kernels. */
choke me
#endif
]])],
[gl_cv_func_utimensat_works=yes],
[gl_cv_func_utimensat_works="needs runtime check"])],
[gl_cv_func_utimensat_works=no],
[gl_cv_func_utimensat_works="guessing no"])])
if test "$gl_cv_func_utimensat_works" != yes; then
REPLACE_UTIMENSAT=1
AC_LIBOBJ([utimensat])
fi
fi
])
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