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# serial 5
# See if we need to provide utimensat replacement.
dnl Copyright (C) 2009-2012 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 $ac_cv_func_utimensat = no; then
HAVE_UTIMENSAT=0
else
AC_CACHE_CHECK([whether utimensat works],
[gl_cv_func_utimensat_works],
[AC_RUN_IFELSE(
[AC_LANG_PROGRAM([[
#include <fcntl.h>
#include <sys/stat.h>
#include <unistd.h>
]], [[int result = 0;
const char *f = "conftest.file";
if (close (creat (f, 0600)))
return 1;
/* Test whether the AT_SYMLINK_NOFOLLOW flag is supported. */
{
if (utimensat (AT_FDCWD, f, NULL, AT_SYMLINK_NOFOLLOW))
result |= 2;
}
/* Test whether UTIME_NOW and UTIME_OMIT work. */
{
struct timespec ts[2] = { { 1, UTIME_OMIT }, { 1, UTIME_NOW } };
if (utimensat (AT_FDCWD, f, ts, 0))
result |= 4;
}
sleep (1);
{
struct timespec ts[2] = { { 1, UTIME_NOW }, { 1, UTIME_OMIT } };
struct stat st;
if (utimensat (AT_FDCWD, f, ts, 0))
result |= 8;
if (stat (f, &st))
result |= 16;
else if (st.st_ctime < st.st_atime)
result |= 32;
}
return result;
]])],
dnl FIXME: simplify this in 2012, when file system bugs are no longer common
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
#ifdef __linux__
/* The Linux kernel added utimensat in 2.6.22, but has bugs with UTIME_OMIT
in several file systems as recently as 2.6.32. Always replace utimensat
to support older kernels. */
choke me
#endif
]])],
[gl_cv_func_utimensat_works=yes],
[gl_cv_func_utimensat_works="needs runtime check"])],
[gl_cv_func_utimensat_works=no],
[gl_cv_func_utimensat_works="guessing no"])])
if test "$gl_cv_func_utimensat_works" != yes; then
REPLACE_UTIMENSAT=1
fi
fi
])
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