dirfd: Avoid link error on AIX 7.1.

[gnulib.git] / m4 / dirfd.m4

diff --git a/m4/dirfd.m4 b/m4/dirfd.m4
index f18bf80..48b7bae 100644 (file)
--- a/m4/dirfd.m4
+++ b/m4/dirfd.m4
@@ -1,68 +1,85 @@
-#serial 1
+# serial 18   -*- Autoconf -*-
 
 dnl Find out how to get the file descriptor associated with an open DIR*.
+
+# Copyright (C) 2001-2006, 2008-2010 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
 dnl From Jim Meyering
 
-AC_DEFUN([UTILS_FUNC_DIRFD],
+AC_DEFUN([gl_FUNC_DIRFD],
 [
-  AC_HEADER_DIRENT
-  dirfd_headers='
-#if HAVE_DIRENT_H
-# include <dirent.h>
-#else /* not HAVE_DIRENT_H */
-# define dirent direct
-# if HAVE_SYS_NDIR_H
-#  include <sys/ndir.h>
-# endif /* HAVE_SYS_NDIR_H */
-# if HAVE_SYS_DIR_H
-#  include <sys/dir.h>
-# endif /* HAVE_SYS_DIR_H */
-# if HAVE_NDIR_H
-#  include <ndir.h>
-# endif /* HAVE_NDIR_H */
-#endif /* HAVE_DIRENT_H */
-'
-  AC_CHECK_FUNCS(dirfd)
-  AC_CHECK_DECLS([dirfd], , , $dirfd_headers)
+  AC_REQUIRE([gl_DIRENT_H_DEFAULTS])
+  gl_REPLACE_DIRENT_H
+
+  dnl Persuade glibc <dirent.h> to declare dirfd().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  dnl Work around a bug of AC_EGREP_CPP in autoconf-2.57.
+  AC_REQUIRE([AC_PROG_CPP])
+  AC_REQUIRE([AC_PROG_EGREP])
+
+  AC_CHECK_FUNCS([dirfd])
+  AC_CHECK_DECLS([dirfd], , ,
+    [#include <sys/types.h>
+     #include <dirent.h>])
+  if test $ac_cv_have_decl_dirfd = no; then
+    HAVE_DECL_DIRFD=0
+  fi
+
+  AC_CACHE_CHECK([whether dirfd is a macro],
+    gl_cv_func_dirfd_macro,
+    [AC_EGREP_CPP([dirent_header_defines_dirfd], [
+#include <sys/types.h>
+#include <dirent.h>
+#ifdef dirfd
+ dirent_header_defines_dirfd
+#endif],
+       gl_cv_func_dirfd_macro=yes,
+       gl_cv_func_dirfd_macro=no)])
 
-  # Use the replacement only if we have neither the function
-  # nor a declaration.
-  if test $ac_cv_func_dirfd,$ac_cv_have_decl_dirfd = no,no; then
-    AC_REPLACE_FUNCS([dirfd])
+  # Use the replacement only if we have no function or macro with that name.
+  if test $ac_cv_func_dirfd,$gl_cv_func_dirfd_macro = no,no; then
+    if test $ac_cv_have_decl_dirfd = yes; then
+      # If the system declares dirfd already, let's declare rpl_dirfd instead.
+      REPLACE_DIRFD=1
+    fi
+    AC_LIBOBJ([dirfd])
     AC_CACHE_CHECK(
-             [how to get the file descriptor associated with an open DIR*],
-                  ac_cv_sys_dir_fd_member_name,
+              [how to get the file descriptor associated with an open DIR*],
+                   gl_cv_sys_dir_fd_member_name,
       [
         dirfd_save_CFLAGS=$CFLAGS
-       for ac_expr in d_fd dd_fd; do
+        for ac_expr in d_fd dd_fd; do
 
-         CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr"
-         AC_TRY_COMPILE(
-           [$dirfd_headers
-           ],
-           [DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;],
-           dir_fd_found=yes
-         )
-         CFLAGS=$dirfd_save_CFLAGS
-         test "$dir_fd_found" = yes && break
-       done
-       test "$dir_fd_found" = yes || ac_expr=-1
+          CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr"
+          AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+             #include <sys/types.h>
+             #include <dirent.h>]],
+            [[DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;]])],
+            [dir_fd_found=yes]
+          )
+          CFLAGS=$dirfd_save_CFLAGS
+          test "$dir_fd_found" = yes && break
+        done
+        test "$dir_fd_found" = yes || ac_expr=no_such_member
 
-       ac_cv_sys_dir_fd_member_name=$ac_expr
+        gl_cv_sys_dir_fd_member_name=$ac_expr
       ]
     )
-    if test $ac_cv_have_decl_dirfd = -1; then
-      AC_DEFINE_UNQUOTED(DIR_FD_MEMBER_NAME,
-       $ac_cv_sys_dir_fd_member_name,
-       [the name of the file descriptor member of DIR])
+    if test $gl_cv_sys_dir_fd_member_name != no_such_member; then
+      AC_DEFINE_UNQUOTED([DIR_FD_MEMBER_NAME],
+        $gl_cv_sys_dir_fd_member_name,
+        [the name of the file descriptor member of DIR])
     fi
     AH_VERBATIM(DIR_TO_FD,
-               [#ifdef DIR_FD_MEMBER_NAME
+                [#ifdef DIR_FD_MEMBER_NAME
 # define DIR_TO_FD(Dir_p) ((Dir_p)->DIR_FD_MEMBER_NAME)
 #else
 # define DIR_TO_FD(Dir_p) -1
 #endif
-]
-    )
+])
   fi
 ])