Manual: improve out-of-memory documentation.

[gnulib.git] / m4 / dos.m4

diff --git a/m4/dos.m4 b/m4/dos.m4
index 618c1f4..5660542 100644 (file)
--- a/m4/dos.m4
+++ b/m4/dos.m4
@@ -1,41 +1,71 @@
-# serial 3
+#serial 11   -*- autoconf -*-
 
 # Define some macros required for proper operation of code in lib/*.c
 # on MSDOS/Windows systems.
 
+# Copyright (C) 2000-2001, 2004-2006, 2009-2010 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.
+
 # From Jim Meyering.
 
-AC_DEFUN(jm_AC_DOS,
+AC_DEFUN([gl_AC_DOS],
   [
-    # FIXME: this is incomplete.  Add a compile-test that does something
-    # like this:
-    #if defined _WIN32 || defined __WIN32__ || defined __MSDOS__
-
-    AH_VERBATIM(FILESYSTEM_PREFIX_LEN,
-    [#if FILESYSTEM_ACCEPTS_DRIVE_LETTER_PREFIX
-# define FILESYSTEM_PREFIX_LEN(Filename) \
-  ((Filename)[0] && (Filename)[1] == ':' ? 2 : 0)
-else
-# define FILESYSTEM_PREFIX_LEN(Filename) 0
-#endif])
+    AC_CACHE_CHECK([whether system is Windows or MSDOS], [ac_cv_win_or_dos],
+      [
+        AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [[
+#if !defined _WIN32 && !defined __WIN32__ && !defined __MSDOS__ && !defined __CYGWIN__
+neither MSDOS nor Windows
+#endif]])],
+        [ac_cv_win_or_dos=yes],
+        [ac_cv_win_or_dos=no])
+      ])
 
-    ac_fs_accepts_drive_letter_prefix=0
-    AC_DEFINE_UNQUOTED([FILESYSTEM_ACCEPTS_DRIVE_LETTER_PREFIX],
+    if test x"$ac_cv_win_or_dos" = xyes; then
+      ac_fs_accepts_drive_letter_prefix=1
+      ac_fs_backslash_is_file_name_separator=1
+      AC_CACHE_CHECK([whether drive letter can start relative path],
+                     [ac_cv_drive_letter_can_be_relative],
+        [
+          AC_COMPILE_IFELSE([AC_LANG_PROGRAM([], [[
+#if defined __CYGWIN__
+drive letters are always absolute
+#endif]])],
+          [ac_cv_drive_letter_can_be_relative=yes],
+          [ac_cv_drive_letter_can_be_relative=no])
+        ])
+      if test x"$ac_cv_drive_letter_can_be_relative" = xyes; then
+        ac_fs_drive_letter_can_be_relative=1
+      else
+        ac_fs_drive_letter_can_be_relative=0
+      fi
+    else
+      ac_fs_accepts_drive_letter_prefix=0
+      ac_fs_backslash_is_file_name_separator=0
+      ac_fs_drive_letter_can_be_relative=0
+    fi
+
+    AC_DEFINE_UNQUOTED([FILE_SYSTEM_ACCEPTS_DRIVE_LETTER_PREFIX],
       $ac_fs_accepts_drive_letter_prefix,
       [Define on systems for which file names may have a so-called
        `drive letter' prefix, define this to compute the length of that
        prefix, including the colon.])
 
     AH_VERBATIM(ISSLASH,
-    [#if FILESYSTEM_BACKSLASH_IS_FILE_NAME_SEPARATOR
+    [#if FILE_SYSTEM_BACKSLASH_IS_FILE_NAME_SEPARATOR
 # define ISSLASH(C) ((C) == '/' || (C) == '\\')
 #else
 # define ISSLASH(C) ((C) == '/')
 #endif])
 
-    ac_fs_backslash_is_file_name_separator=0
-    AC_DEFINE_UNQUOTED([FILESYSTEM_BACKSLASH_IS_FILE_NAME_SEPARATOR],
+    AC_DEFINE_UNQUOTED([FILE_SYSTEM_BACKSLASH_IS_FILE_NAME_SEPARATOR],
       $ac_fs_backslash_is_file_name_separator,
       [Define if the backslash character may also serve as a file name
        component separator.])
+
+    AC_DEFINE_UNQUOTED([FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE],
+      $ac_fs_drive_letter_can_be_relative,
+      [Define if a drive letter prefix denotes a relative path if it is
+       not followed by a file name component separator.])
   ])