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# fcntl-o.m4 serial 1
dnl Copyright (C) 2006, 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.
dnl Written by Paul Eggert.
# Test whether the flags O_NOATIME and O_NOFOLLOW actually work.
# Define HAVE_WORKING_O_NOATIME to 1 if O_NOATIME works, or to 0 otherwise.
# Define HAVE_WORKING_O_NOFOLLOW to 1 if O_NOFOLLOW works, or to 0 otherwise.
AC_DEFUN([gl_FCNTL_O_FLAGS],
[
dnl Persuade glibc <fcntl.h> to define O_NOATIME and O_NOFOLLOW.
AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
AC_CACHE_CHECK([for working fcntl.h], [gl_cv_header_working_fcntl_h],
[AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[[#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#ifndef O_NOATIME
#define O_NOATIME 0
#endif
#ifndef O_NOFOLLOW
#define O_NOFOLLOW 0
#endif
static int const constants[] =
{
O_CREAT, O_EXCL, O_NOCTTY, O_TRUNC, O_APPEND,
O_NONBLOCK, O_SYNC, O_ACCMODE, O_RDONLY, O_RDWR, O_WRONLY
};
]],
[[
int status = !constants;
{
static char const sym[] = "conftest.sym";
if (symlink (".", sym) != 0
|| close (open (sym, O_RDONLY | O_NOFOLLOW)) == 0)
status |= 32;
unlink (sym);
}
{
static char const file[] = "confdefs.h";
int fd = open (file, O_RDONLY | O_NOATIME);
char c;
struct stat st0, st1;
if (fd < 0
|| fstat (fd, &st0) != 0
|| sleep (1) != 0
|| read (fd, &c, 1) != 1
|| close (fd) != 0
|| stat (file, &st1) != 0
|| st0.st_atime != st1.st_atime)
status |= 64;
}
return status;]])],
[gl_cv_header_working_fcntl_h=yes],
[case $? in #(
32) gl_cv_header_working_fcntl_h='no (bad O_NOFOLLOW)';; #(
64) gl_cv_header_working_fcntl_h='no (bad O_NOATIME)';; #(
96) gl_cv_header_working_fcntl_h='no (bad O_NOATIME, O_NOFOLLOW)';; #(
*) gl_cv_header_working_fcntl_h='no';;
esac],
[gl_cv_header_working_fcntl_h=cross-compiling])])
case $gl_cv_header_working_fcntl_h in #(
*O_NOATIME* | no | cross-compiling) ac_val=0;; #(
*) ac_val=1;;
esac
AC_DEFINE_UNQUOTED([HAVE_WORKING_O_NOATIME], [$ac_val],
[Define to 1 if O_NOATIME works.])
case $gl_cv_header_working_fcntl_h in #(
*O_NOFOLLOW* | no | cross-compiling) ac_val=0;; #(
*) ac_val=1;;
esac
AC_DEFINE_UNQUOTED([HAVE_WORKING_O_NOFOLLOW], [$ac_val],
[Define to 1 if O_NOFOLLOW works.])
])
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