X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fdirfd.m4;h=02ddc9f787f448ca91a577482bd73c3adc754551;hb=3f0d472e052865baf722ea457e35dd067b94a477;hp=fee5fb2ec7a7045c5d72b277daf6d95ca62434c2;hpb=39ce2a1909d1f2562f4a59974b97d3ec6217c5bc;p=gnulib.git

diff --git a/m4/dirfd.m4 b/m4/dirfd.m4
index fee5fb2ec..02ddc9f78 100644
--- a/m4/dirfd.m4
+++ b/m4/dirfd.m4
@@ -1,66 +1,83 @@
-#serial 1
+# serial 17   -*- Autoconf -*-
 
 dnl Find out how to get the file descriptor associated with an open DIR*.
+
+# Copyright (C) 2001-2006, 2008-2009 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
-  AC_REPLACE_FUNCS([dirfd])
-  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_DECLS([dirfd], , , $dirfd_headers)
-  if test $ac_cv_func_dirfd = no; then
+  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 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						\
-								\
-	    '# Solaris'						\
-	    'dir_p->d_fd'					\
-								\
-	    '# Solaris'						\
-	    'dir_p->dd_fd'					\
-								\
-	    '# systems for which the info is not available'	\
-	    -1							\
-	    ; do
+	dirfd_save_CFLAGS=$CFLAGS
+	for ac_expr in d_fd dd_fd; do
 
-	  # Skip each embedded comment.
-	  case "$ac_expr" in '#'*) continue;; esac
-
-	  DEFS="$DEFS -DDIR_TO_FD=$ac_expr"
-	  AC_TRY_COMPILE(
-	    [$dirfd_headers
-	    ],
-	    [DIR *dir_p = opendir("."); (void) ($ac_expr);],
-	    dir_fd_done=yes
+	  CFLAGS="$CFLAGS -DDIR_FD_MEMBER_NAME=$ac_expr"
+	  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+	     #include <sys/types.h>
+	     #include <dirent.h>]],
+	    [[DIR *dir_p = opendir("."); (void) dir_p->DIR_FD_MEMBER_NAME;]])],
+	    [dir_fd_found=yes]
 	  )
-	  DEFS=$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
 ])