X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fdirfd.m4;h=db2a9a0eda6a7533c91fe6006c071238457a6e0c;hb=9df4453b386268b137f71b0e9548f67e03565dd4;hp=9b6fb457edb14f94c5f958a1a864cd34ddac81be;hpb=400d9b8d89a4c51465bee4f747e076dc8d72985a;p=gnulib.git

diff --git a/m4/dirfd.m4 b/m4/dirfd.m4
index 9b6fb457e..db2a9a0ed 100644
--- a/m4/dirfd.m4
+++ b/m4/dirfd.m4
@@ -1,10 +1,22 @@
-#serial 1
+#serial 10
 
 dnl Find out how to get the file descriptor associated with an open DIR*.
+
+# Copyright (C) 2001, 2002, 2003, 2004, 2005 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_LIBSOURCES([dirfd.c, dirfd.h])
+
+  dnl Work around a bug of AC_EGREP_CPP in autoconf-2.57.
+  AC_REQUIRE([AC_PROG_CPP])
+  AC_REQUIRE([AC_PROG_EGREP])
+
   AC_HEADER_DIRENT
   dirfd_headers='
 #if HAVE_DIRENT_H
@@ -25,44 +37,53 @@ AC_DEFUN([UTILS_FUNC_DIRFD],
   AC_CHECK_FUNCS(dirfd)
   AC_CHECK_DECLS([dirfd], , , $dirfd_headers)
 
-  # 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_CACHE_CHECK([whether dirfd is a macro],
+    gl_cv_func_dirfd_macro,
+    [AC_EGREP_CPP([dirent_header_defines_dirfd], [$dirfd_headers
+#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 no function, macro,
+  # or declaration with that name.
+  if test $ac_cv_func_dirfd,$ac_cv_have_decl_dirfd,$gl_cv_func_dirfd_macro \
+      = no,no,no; then
     AC_REPLACE_FUNCS([dirfd])
     AC_CACHE_CHECK(
 	      [how to get the file descriptor associated with an open DIR*],
-		   ac_cv_sys_dir_to_fd,
+		   gl_cv_sys_dir_fd_member_name,
       [
-        dirfd_save_DEFS=$DEFS
-	for ac_expr in						\
-								\
-	    'dir_p->d_fd'					\
-								\
-	    'dir_p->dd_fd'					\
-								\
-	    '# systems for which the info is not available'	\
-	    -1							\
-	    ; do
-
-	  # Skip each embedded comment.
-	  case "$ac_expr" in '#'*) continue;; esac
+        dirfd_save_CFLAGS=$CFLAGS
+	for ac_expr in d_fd dd_fd; do
 
-	  DEFS="$DEFS -DDIR_TO_FD=$ac_expr"
+	  CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr"
 	  AC_TRY_COMPILE(
 	    [$dirfd_headers
 	    ],
-	    [DIR *dir_p = opendir("."); (void) ($ac_expr);],
-	    dir_fd_done=yes
+	    [DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;],
+	    dir_fd_found=yes
 	  )
-	  DEFS=$dirfd_save_DEFS
-	  test "$dir_fd_done" = yes && break
+	  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_to_fd=$ac_expr
+	gl_cv_sys_dir_fd_member_name=$ac_expr
       ]
     )
-    AC_DEFINE_UNQUOTED(DIR_TO_FD,
-      $ac_cv_sys_dir_to_fd,
-      [the file descriptor associated with `dir_p'])
+    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
+# define DIR_TO_FD(Dir_p) ((Dir_p)->DIR_FD_MEMBER_NAME)
+#else
+# define DIR_TO_FD(Dir_p) -1
+#endif
+])
   fi
 ])