1# fchdir.m4 serial 27 2dnl Copyright (C) 2006-2022 Free Software Foundation, Inc. 3dnl This file is free software; the Free Software Foundation 4dnl gives unlimited permission to copy and/or distribute it, 5dnl with or without modifications, as long as this notice is preserved. 6 7AC_DEFUN([gl_FUNC_FCHDIR], 8[ 9 AC_REQUIRE([gl_UNISTD_H_DEFAULTS]) 10 AC_REQUIRE([gl_DIRENT_H_DEFAULTS]) 11 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles 12 13 AC_CHECK_DECLS_ONCE([fchdir]) 14 if test $ac_cv_have_decl_fchdir = no; then 15 HAVE_DECL_FCHDIR=0 16 fi 17 18 AC_REQUIRE([gl_TEST_FCHDIR]) 19 if test $HAVE_FCHDIR = 0; then 20 AC_DEFINE([REPLACE_FCHDIR], [1], 21 [Define to 1 if gnulib's fchdir() replacement is used.]) 22 dnl We must also replace anything that can manipulate a directory fd, 23 dnl to keep our bookkeeping up-to-date. We don't have to replace 24 dnl fstatat, since no platform has fstatat but lacks fchdir. 25 AC_CACHE_CHECK([whether open can visit directories], 26 [gl_cv_func_open_directory_works], 27 [AC_RUN_IFELSE( 28 [AC_LANG_PROGRAM( 29 [[#include <fcntl.h> 30 ]GL_MDA_DEFINES], 31 [[return open(".", O_RDONLY) < 0;]])], 32 [gl_cv_func_open_directory_works=yes], 33 [gl_cv_func_open_directory_works=no], 34 [case "$host_os" in 35 # Guess yes on Linux systems. 36 linux-* | linux) gl_cv_func_open_directory_works="guessing yes" ;; 37 # Guess yes on glibc systems. 38 *-gnu* | gnu*) gl_cv_func_open_directory_works="guessing yes" ;; 39 # Guess no on native Windows. 40 mingw*) gl_cv_func_open_directory_works="guessing no" ;; 41 # If we don't know, obey --enable-cross-guesses. 42 *) gl_cv_func_open_directory_works="$gl_cross_guess_normal" ;; 43 esac 44 ])]) 45 case "$gl_cv_func_open_directory_works" in 46 *yes) ;; 47 *) 48 AC_DEFINE([REPLACE_OPEN_DIRECTORY], [1], [Define to 1 if open() should 49work around the inability to open a directory.]) 50 ;; 51 esac 52 fi 53]) 54 55# Determine whether to use the overrides in lib/fchdir.c. 56AC_DEFUN([gl_TEST_FCHDIR], 57[ 58 AC_REQUIRE([gl_UNISTD_H_DEFAULTS]) 59 AC_CHECK_FUNCS_ONCE([fchdir]) 60 if test $ac_cv_func_fchdir = no; then 61 HAVE_FCHDIR=0 62 fi 63]) 64 65# Prerequisites of lib/fchdir.c. 66AC_DEFUN([gl_PREREQ_FCHDIR], [:]) 67