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# fchdir.m4 serial 29
dnl Copyright (C) 2006-2023 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.
AC_DEFUN([gl_FUNC_FCHDIR],
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
AC_CHECK_DECLS_ONCE([fchdir])
if test $ac_cv_have_decl_fchdir = no; then
HAVE_DECL_FCHDIR=0
fi
AC_REQUIRE([gl_TEST_FCHDIR])
if test $HAVE_FCHDIR = 0; then
AC_DEFINE([REPLACE_FCHDIR], [1],
[Define to 1 if gnulib's fchdir() replacement is used.])
dnl We must also replace anything that can manipulate a directory fd,
dnl to keep our bookkeeping up-to-date. We don't have to replace
dnl fstatat, since no platform has fstatat but lacks fchdir.
AC_CACHE_CHECK([whether open can visit directories],
[gl_cv_func_open_directory_works],
[AC_RUN_IFELSE(
[AC_LANG_PROGRAM(
[[#include <fcntl.h>
]GL_MDA_DEFINES],
[[return open(".", O_RDONLY) < 0;]])],
[gl_cv_func_open_directory_works=yes],
[gl_cv_func_open_directory_works=no],
[case "$host_os" in
# Guess yes on Linux systems.
linux-* | linux) gl_cv_func_open_directory_works="guessing yes" ;;
# Guess yes on systems that emulate the Linux system calls.
midipix*) gl_cv_func_open_directory_works="guessing yes" ;;
# Guess yes on glibc systems.
*-gnu* | gnu*) gl_cv_func_open_directory_works="guessing yes" ;;
# Guess no on native Windows.
mingw* | windows*) gl_cv_func_open_directory_works="guessing no" ;;
# If we don't know, obey --enable-cross-guesses.
*) gl_cv_func_open_directory_works="$gl_cross_guess_normal" ;;
esac
])])
case "$gl_cv_func_open_directory_works" in
*yes) ;;
*)
AC_DEFINE([REPLACE_OPEN_DIRECTORY], [1], [Define to 1 if open() should
work around the inability to open a directory.])
;;
esac
fi
])
# Determine whether to use the overrides in lib/fchdir.c.
AC_DEFUN([gl_TEST_FCHDIR],
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
AC_CHECK_FUNCS_ONCE([fchdir])
if test $ac_cv_func_fchdir = no; then
HAVE_FCHDIR=0
fi
])
# Prerequisites of lib/fchdir.c.
AC_DEFUN([gl_PREREQ_FCHDIR], [:])
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