1 files changed, 414 insertions, 233 deletions

diff --git a/src/fileio.c b/src/fileio.c
index 7493a29f1a4..d01b70c7af7 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -1,5 +1,5 @@
 /* File IO for GNU Emacs.
-   Copyright (C) 1985, 86, 87, 88, 93, 94, 95 Free Software Foundation, Inc.
+   Copyright (C) 1985,86,87,88,93,94,95,96 Free Software Foundation, Inc.
 
 This file is part of GNU Emacs.
 
@@ -93,6 +93,21 @@ extern char *strerror ();
 #include <fcntl.h>
 #endif /* not WINDOWSNT */
 
+#ifdef DOS_NT
+#define CORRECT_DIR_SEPS(s) \
+  do { if ('/' == DIRECTORY_SEP) dostounix_filename (s); \
+       else unixtodos_filename (s); \
+  } while (0)
+/* On Windows, drive letters must be alphabetic - on DOS, the Netware
+   redirector allows the six letters between 'Z' and 'a' as well. */
+#ifdef MSDOS
+#define IS_DRIVE(x) ((x) >= 'A' && (x) <= 'z')
+#endif
+#ifdef WINDOWSNT
+#define IS_DRIVE(x) isalpha (x)
+#endif
+#endif
+
 #ifdef VMS
 #include <file.h>
 #include <rmsdef.h>
@@ -129,7 +144,7 @@ int auto_saving;
    a new file with the same mode as the original */
 int auto_save_mode_bits;
 
-/* Alist of elements (REGEXP . HANDLER) for file names 
+/* Alist of elements (REGEXP . HANDLER) for file names
    whose I/O is done with a special handler.  */
 Lisp_Object Vfile_name_handler_alist;
 
@@ -160,6 +175,10 @@ int insert_default_directory;
    Zero means use var format.  */
 int vms_stmlf_recfm;
 
+/* On NT, specifies the directory separator character, used (eg.) when
+   expanding file names.  This can be bound to / or \. */
+Lisp_Object Vdirectory_sep_char;
+
 /* These variables describe handlers that have "already" had a chance
    to handle the current operation.
 
@@ -203,7 +222,7 @@ close_file_unwind (fd)
 /* Restore point, having saved it as a marker.  */
 
 restore_point_unwind (location)
-     Lisp_Object location; 
+     Lisp_Object location;
 {
   SET_PT (marker_position (location));
   Fset_marker (location, Qnil, Qnil);
@@ -312,44 +331,38 @@ on VMS, perhaps instead a string ending in `:', `]' or `>'.")
   filename = FILE_SYSTEM_CASE (filename);
 #endif
   beg = XSTRING (filename)->data;
+#ifdef DOS_NT
+  beg = strcpy (alloca (strlen (beg) + 1), beg);
+#endif
   p = beg + XSTRING (filename)->size;
 
-  while (p != beg && !IS_ANY_SEP (p[-1])
+  while (p != beg && !IS_DIRECTORY_SEP (p[-1])
 #ifdef VMS
          && p[-1] != ':' && p[-1] != ']' && p[-1] != '>'
 #endif /* VMS */
+#ifdef DOS_NT
+         /* only recognise drive specifier at beginning */
+         && !(p[-1] == ':' && p == beg + 2)
+#endif
          ) p--;
 
   if (p == beg)
     return Qnil;
 #ifdef DOS_NT
   /* Expansion of "c:" to drive and default directory.  */
-  /* (NT does the right thing.)  */
   if (p == beg + 2 && beg[1] == ':')
     {
-      int drive = (*beg) - 'a';
       /* MAXPATHLEN+1 is guaranteed to be enough space for getdefdir.  */
-      unsigned char *res = alloca (MAXPATHLEN + 5);
-      unsigned char *res1;
-#ifdef WINDOWSNT
-      res1 = res;
-      /* The NT version places the drive letter at the beginning already.  */
-#else /* not WINDOWSNT */
-      /* On MSDOG we must put the drive letter in by hand.  */
-      res1 = res + 2;
-#endif /* not WINDOWSNT */
-      if (getdefdir (drive + 1, res)) 
+      unsigned char *res = alloca (MAXPATHLEN + 1);
+      if (getdefdir (toupper (*beg) - 'A' + 1, res))
         {
-#ifdef MSDOS
-          res[0] = drive + 'a';
-          res[1] = ':';
-#endif /* MSDOS */
-          if (IS_DIRECTORY_SEP (res[strlen (res) - 1]))
+          if (!IS_DIRECTORY_SEP (res[strlen (res) - 1]))
             strcat (res, "/");
           beg = res;
           p = beg + strlen (beg);
         }
     }
+  CORRECT_DIR_SEPS (beg);
 #endif /* DOS_NT */
   return make_string (beg, p - beg);
 }
@@ -377,10 +390,14 @@ or the entire name if it contains no slash.")
   beg = XSTRING (filename)->data;
   end = p = beg + XSTRING (filename)->size;
 
-  while (p != beg && !IS_ANY_SEP (p[-1])
+  while (p != beg && !IS_DIRECTORY_SEP (p[-1])
 #ifdef VMS
          && p[-1] != ':' && p[-1] != ']' && p[-1] != '>'
 #endif /* VMS */
+#ifdef DOS_NT
+         /* only recognise drive specifier at beginning */
+         && !(p[-1] == ':' && p == beg + 2)
+#endif
          ) p--;
 
   return make_string (p, end - p);
@@ -476,11 +493,14 @@ file_name_as_directory (out, in)
     }
 #else /* not VMS */
   /* For Unix syntax, Append a slash if necessary */
-  if (!IS_ANY_SEP (out[size]))
+  if (!IS_DIRECTORY_SEP (out[size]))
     {
       out[size + 1] = DIRECTORY_SEP;
       out[size + 2] = '\0';
     }
+#ifdef DOS_NT
+  CORRECT_DIR_SEPS (out);
+#endif
 #endif /* not VMS */
   return out;
 }
@@ -519,7 +539,7 @@ On VMS, converts \"[X]FOO.DIR\" to \"[X.FOO]\", etc.")
  * On VMS:
  *       xyzzy:[mukesh.emacs] => xyzzy:[mukesh]emacs.dir.1
  *       xyzzy:[mukesh] => xyzzy:[000000]mukesh.dir.1
- * On UNIX, it's simple: just make sure there is a terminating /
+ * On UNIX, it's simple: just make sure there isn't a terminating /
 
  * Value is nonzero if the string output is different from the input.
  */
@@ -555,7 +575,7 @@ directory_file_name (src, dst)
       nam.nam$b_nop |= NAM$M_SYNCHK;
 
       /* We call SYS$PARSE to handle such things as [--] for us. */
-      if (SYS$PARSE(&fab, 0, 0) == RMS$_NORMAL)
+      if (SYS$PARSE (&fab, 0, 0) == RMS$_NORMAL)
         {
           slen = nam.nam$b_esl;
           if (esa[slen - 1] == ';' && esa[slen - 2] == '.')
@@ -624,7 +644,7 @@ directory_file_name (src, dst)
              then translate the device and recurse. */
           if (dst[slen - 1] == ':'
               && dst[slen - 2] != ':'   /* skip decnet nodes */
-              && strcmp(src + slen, "[000000]") == 0)
+              && strcmp (src + slen, "[000000]") == 0)
             {
               dst[slen - 1] = '\0';
               if ((ptr = egetenv (dst))
@@ -661,7 +681,7 @@ directory_file_name (src, dst)
       || (slen > 1 && dst[0] != '/' && dst[slen - 1] == '/'))
     dst[slen - 1] = 0;
 #else
-  if (slen > 1 
+  if (slen > 1
       && IS_DIRECTORY_SEP (dst[slen - 1])
 #ifdef DOS_NT
       && !IS_ANY_SEP (dst[slen - 2])
@@ -669,6 +689,9 @@ directory_file_name (src, dst)
       )
     dst[slen - 1] = 0;
 #endif
+#ifdef DOS_NT
+  CORRECT_DIR_SEPS (dst);
+#endif
   return 1;
 }
 
@@ -726,6 +749,9 @@ so there is no danger of generating a name being used by another process.")
   val = concat2 (prefix, build_string ("XXXXXX"));
 #endif
   mktemp (XSTRING (val)->data);
+#ifdef DOS_NT
+  CORRECT_DIR_SEPS (XSTRING (val)->data);
+#endif
   return val;
 }
 
@@ -734,10 +760,10 @@ DEFUN ("expand-file-name", Fexpand_file_name, Sexpand_file_name, 1, 2, 0,
 Second arg DEFAULT-DIRECTORY is directory to start with if NAME is relative\n\
  (does not start with slash); if DEFAULT-DIRECTORY is nil or missing,\n\
 the current buffer's value of default-directory is used.\n\
-Path components that are `.' are removed, and \n\
-path components followed by `..' are removed, along with the `..' itself;\n\
+File name components that are `.' are removed, and \n\
+so are file name components followed by `..', along with the `..' itself;\n\
 note that these simplifications are done without checking the resulting\n\
-paths in the file system.\n\
+file names in the file system.\n\
 An initial `~/' expands to your home directory.\n\
 An initial `~USER/' expands to USER's home directory.\n\
 See also the function `substitute-in-file-name'.")
@@ -745,7 +771,7 @@ See also the function `substitute-in-file-name'.")
      Lisp_Object name, default_directory;
 {
   unsigned char *nm;
-  
+
   register unsigned char *newdir, *p, *o;
   int tlen;
   unsigned char *target;
@@ -759,13 +785,11 @@ See also the function `substitute-in-file-name'.")
   int dots = 0;
 #endif /* VMS */
 #ifdef DOS_NT
-  /* Demacs 1.1.2 91/10/20 Manabu Higashida */
-  int drive = -1;
-  int relpath = 0;
-  unsigned char *tmp, *defdir;
+  int drive = 0;
 #endif /* DOS_NT */
+  int length;
   Lisp_Object handler;
-  
+
   CHECK_STRING (name, 0);
 
   /* If the file name has special constructs in it,
@@ -799,15 +823,22 @@ See also the function `substitute-in-file-name'.")
 
      The EQ test avoids infinite recursion.  */
   if (! NILP (default_directory) && !EQ (default_directory, name)
-      /* Save time in some common cases.  */
+      /* Save time in some common cases - as long as default_directory
+         is not relative, it can be canonicalized with name below (if it
+         is needed at all) without requiring it to be expanded now.  */
 #ifdef DOS_NT
-      /* Detect MSDOS file names with device names.  */
-      && ! (XSTRING (default_directory)->size >= 3
-            && IS_DEVICE_SEP (o[1]) && IS_DIRECTORY_SEP (o[2]))
+      /* Detect MSDOS file names with drive specifiers.  */
+      && ! (IS_DRIVE (o[0]) && (IS_DEVICE_SEP (o[1]) && IS_DIRECTORY_SEP (o[2])))
+#ifdef WINDOWSNT
+      /* Detect Windows file names in UNC format.  */
+      && ! (IS_DIRECTORY_SEP (o[0]) && IS_DIRECTORY_SEP (o[1]))
 #endif
-      /* Detect Unix absolute file names.  */
-      && ! (XSTRING (default_directory)->size >= 2
-            && IS_DIRECTORY_SEP (o[0])))
+#else /* not DOS_NT */
+      /* Detect Unix absolute file names (/... alone is not absolute on
+         DOS or Windows).  */
+      && ! (IS_DIRECTORY_SEP (o[0]))
+#endif /* not DOS_NT */
+      )
     {
       struct gcpro gcpro1;
 
@@ -825,29 +856,38 @@ See also the function `substitute-in-file-name'.")
 #endif
 
   nm = XSTRING (name)->data;
-  
-#ifdef MSDOS
-  /* First map all backslashes to slashes.  */
-  dostounix_filename (nm = strcpy (alloca (strlen (nm) + 1), nm));
-#endif
 
 #ifdef DOS_NT
-  /* Now strip drive name. */
+  /* We will force directory separators to be either all \ or /, so make
+     a local copy to modify, even if there ends up being no change. */
+  nm = strcpy (alloca (strlen (nm) + 1), nm);
+
+  /* Find and remove drive specifier if present; this makes nm absolute
+     even if the rest of the name appears to be relative. */
   {
     unsigned char *colon = rindex (nm, ':');
+
     if (colon)
+      /* Only recognize colon as part of drive specifier if there is a
+         single alphabetic character preceeding the colon (and if the
+         character before the drive letter, if present, is a directory
+         separator); this is to support the remote system syntax used by
+         ange-ftp, and the "po:username" syntax for POP mailboxes. */
+    look_again:
       if (nm == colon)
         nm++;
-      else
+      else if (IS_DRIVE (colon[-1])
+               && (colon == nm + 1 || IS_DIRECTORY_SEP (colon[-2])))
         {
           drive = colon[-1];
           nm = colon + 1;
-          if (!IS_DIRECTORY_SEP (*nm))
-            {
-              defdir = alloca (MAXPATHLEN + 1);
-              relpath = getdefdir (tolower (drive) - 'a' + 1, defdir);
-            }
-        }       
+        }
+      else
+        {
+          while (--colon >= nm)
+            if (colon[0] == ':')
+              goto look_again;
+        }
   }
 #endif /* DOS_NT */
 
@@ -856,31 +896,43 @@ See also the function `substitute-in-file-name'.")
   p = nm;
   while (*p)
     {
-      /* Since we know the path is absolute, we can assume that each
-         element starts with a "/".  */
+      /* Since we are expecting the name to be absolute, we can assume
+         that each element starts with a "/".  */
 
-      /* "//" anywhere isn't necessarily hairy; we just start afresh
-         with the second slash.  */
       if (IS_DIRECTORY_SEP (p[0]) && IS_DIRECTORY_SEP (p[1])
 #if defined (APOLLO) || defined (WINDOWSNT)
-          /* // at start of filename is meaningful on Apollo 
+          /* // at start of filename is meaningful on Apollo
              and WindowsNT systems */
           && nm != p
 #endif /* APOLLO || WINDOWSNT */
           )
         nm = p + 1;
 
-      /* "~" is hairy as the start of any path element.  */
       if (IS_DIRECTORY_SEP (p[0]) && p[1] == '~')
         nm = p + 1;
 
       p++;
     }
 
-  /* If nm is absolute, flush ...// and detect /./ and /../.
-     If no /./ or /../ we can return right away. */
+#ifdef WINDOWSNT
+  /* Discard any previous drive specifier if nm is now in UNC format. */
+  if (IS_DIRECTORY_SEP (nm[0]) && IS_DIRECTORY_SEP (nm[1]))
+    {
+      drive = 0;
+    }
+#endif
+
+  /* If nm is absolute, look for /./ or /../ sequences; if none are
+     found, we can probably return right away.  We will avoid allocating
+     a new string if name is already fully expanded.  */
   if (
       IS_DIRECTORY_SEP (nm[0])
+#ifdef MSDOS
+      && drive
+#endif
+#ifdef WINDOWSNT
+      && (drive || IS_DIRECTORY_SEP (nm[1]))
+#endif
 #ifdef VMS
       || index (nm, ':')
 #endif /* VMS */
@@ -897,7 +949,7 @@ See also the function `substitute-in-file-name'.")
       p = nm;
       while (*p)
         {
-          /* Since we know the path is absolute, we can assume that each
+          /* Since we know the name is absolute, we can assume that each
              element starts with a "/".  */
 
           /* "." and ".." are hairy.  */
@@ -957,7 +1009,7 @@ See also the function `substitute-in-file-name'.")
                 nm = brack + 1;
                 brack = 0;
               }
-            /* if /pathname/dev:, move nm to dev: */
+            /* if /name/dev:, move nm to dev: */
             else if (slash)
               nm = slash + 1;
             /* if node::dev:, move colon following dev */
@@ -989,7 +1041,28 @@ See also the function `substitute-in-file-name'.")
           if (index (nm, '/'))
             return build_string (sys_translate_unix (nm));
 #endif /* VMS */
-#ifndef DOS_NT
+#ifdef DOS_NT
+          /* Make sure directories are all separated with / or \ as
+             desired, but avoid allocation of a new string when not
+             required. */
+          CORRECT_DIR_SEPS (nm);
+#ifdef WINDOWSNT
+          if (IS_DIRECTORY_SEP (nm[1]))
+            {
+              if (strcmp (nm, XSTRING (name)->data) != 0)
+                name = build_string (nm);
+            }
+          else
+#endif
+          /* drive must be set, so this is okay */
+          if (strcmp (nm - 2, XSTRING (name)->data) != 0)
+            {
+              name = make_string (nm - 2, p - nm + 2);
+              XSTRING (name)->data[0] = drive;
+              XSTRING (name)->data[1] = ':';
+            }
+          return name;
+#else /* not DOS_NT */
           if (nm == XSTRING (name)->data)
             return name;
           return build_string (nm);
@@ -997,7 +1070,21 @@ See also the function `substitute-in-file-name'.")
         }
     }
 
-  /* Now determine directory to start with and put it in newdir */
+  /* At this point, nm might or might not be an absolute file name.  We
+     need to expand ~ or ~user if present, otherwise prefix nm with
+     default_directory if nm is not absolute, and finally collapse /./
+     and /foo/../ sequences.
+
+     We set newdir to be the appropriate prefix if one is needed:
+       - the relevant user directory if nm starts with ~ or ~user
+       - the specified drive's working dir (DOS/NT only) if nm does not
+         start with /
+       - the value of default_directory.
+
+     Note that these prefixes are not guaranteed to be absolute (except
+     for the working dir of a drive).  Therefore, to ensure we always
+     return an absolute name, if the final prefix is not absolute we
+     append it to the current working directory.  */
 
   newdir = 0;
 
@@ -1011,14 +1098,12 @@ See also the function `substitute-in-file-name'.")
         {
           if (!(newdir = (unsigned char *) egetenv ("HOME")))
             newdir = (unsigned char *) "";
+          nm++;
 #ifdef DOS_NT
-          /* Problem when expanding "~\" if HOME is not on current drive.
-             Ulrich Leodolter, Wed Jan 11 10:20:35 1995 */
-          if (newdir[1] == ':')
-            drive = newdir[0];
-          dostounix_filename (newdir);
+          if (IS_DIRECTORY_SEP (nm[0]))
+            /* Make nm look like a relative file name.  */
+            nm++;
 #endif
-          nm++;
 #ifdef VMS
           nm++;                 /* Don't leave the slash in nm.  */
 #endif /* VMS */
@@ -1034,10 +1119,6 @@ See also the function `substitute-in-file-name'.")
           bcopy ((char *) nm, o, p - nm);
           o [p - nm] = 0;
 
-#ifdef  WINDOWSNT
-          newdir = (unsigned char *) egetenv ("HOME");
-          dostounix_filename (newdir);
-#else  /* not WINDOWSNT */
           pw = (struct passwd *) getpwnam (o + 1);
           if (pw)
             {
@@ -1046,41 +1127,136 @@ See also the function `substitute-in-file-name'.")
               nm = p + 1;       /* skip the terminator */
 #else
               nm = p;
+#ifdef DOS_NT
+              if (IS_DIRECTORY_SEP (nm[0]))
+                /* Make nm look like a relative name.  */
+                nm++;
+#endif
 #endif /* VMS */
             }
-#endif /* not WINDOWSNT */
 
           /* If we don't find a user of that name, leave the name
              unchanged; don't move nm forward to p.  */
         }
     }
 
-  if (!IS_ANY_SEP (nm[0])
-#ifdef VMS
-      && !index (nm, ':')
-#endif /* not VMS */
 #ifdef DOS_NT
-      && drive == -1
+  /* On DOS and Windows, nm is absolute if a drive name was specified;
+     use the drive's current directory as the prefix if needed.  */
+  if (!newdir && drive)
+    {
+      /* Get default directory if needed to make nm absolute. */
+      if (!IS_DIRECTORY_SEP (nm[0]))
+        {
+          newdir = alloca (MAXPATHLEN + 1);
+          if (!getdefdir (toupper (drive) - 'A' + 1, newdir))
+            newdir = NULL;
+        }
+      if (!newdir)
+        {
+          /* Either nm starts with /, or drive isn't mounted. */
+          newdir = alloca (4);
+          newdir[0] = drive;
+          newdir[1] = ':';
+          newdir[2] = '/';
+          newdir[3] = 0;
+        }
+    }
 #endif /* DOS_NT */
+
+  /* Finally, if no prefix has been specified and nm is not absolute,
+     then it must be expanded relative to default_directory. */
+
+  if (
+#ifndef DOS_NT
+      /* /... alone is not absolute on DOS and Windows. */
+      !IS_DIRECTORY_SEP (nm[0])
+#endif
+#ifdef WINDOWSNT
+      !(IS_DIRECTORY_SEP (nm[0]) && IS_DIRECTORY_SEP (nm[1]))
+#endif
+#ifdef VMS
+      && !index (nm, ':')
+#endif
       && !newdir)
     {
       newdir = XSTRING (default_directory)->data;
     }
 
 #ifdef DOS_NT
-  if (newdir == 0 && relpath)
-    newdir = defdir; 
+  if (newdir)
+    {
+      /* First ensure newdir is an absolute name. */
+      if (
+          /* Detect MSDOS file names with drive specifiers.  */
+          ! (IS_DRIVE (newdir[0])
+             && IS_DEVICE_SEP (newdir[1]) && IS_DIRECTORY_SEP (newdir[2]))
+#ifdef WINDOWSNT
+          /* Detect Windows file names in UNC format.  */
+          && ! (IS_DIRECTORY_SEP (newdir[0]) && IS_DIRECTORY_SEP (newdir[1]))
+#endif
+          )
+        {
+          /* Effectively, let newdir be (expand-file-name newdir cwd).
+             Because of the admonition against calling expand-file-name
+             when we have pointers into lisp strings, we accomplish this
+             indirectly by prepending newdir to nm if necessary, and using
+             cwd (or the wd of newdir's drive) as the new newdir. */
+
+          if (IS_DRIVE (newdir[0]) && newdir[1] == ':')
+            {
+              drive = newdir[0];
+              newdir += 2;
+            }
+          if (!IS_DIRECTORY_SEP (nm[0]))
+            {
+              char * tmp = alloca (strlen (newdir) + strlen (nm) + 2);
+              file_name_as_directory (tmp, newdir);
+              strcat (tmp, nm);
+              nm = tmp;
+            }
+          newdir = alloca (MAXPATHLEN + 1);
+          if (drive)
+            {
+              if (!getdefdir (toupper (drive) - 'A' + 1, newdir))
+                newdir = "/";
+            }
+          else
+            getwd (newdir);
+        }
+
+      /* Strip off drive name from prefix, if present. */
+      if (IS_DRIVE (newdir[0]) && newdir[1] == ':')
+        {
+          drive = newdir[0];
+          newdir += 2;
+        }
+
+      /* Keep only a prefix from newdir if nm starts with slash
+         (//server/share for UNC, nothing otherwise). */
+      if (IS_DIRECTORY_SEP (nm[0]))
+        {
+#ifdef WINDOWSNT
+          if (IS_DIRECTORY_SEP (newdir[0]) && IS_DIRECTORY_SEP (newdir[1]))
+            {
+              newdir = strcpy (alloca (strlen (newdir) + 1), newdir);
+              p = newdir + 2;
+              while (*p && !IS_DIRECTORY_SEP (*p)) p++;
+              p++;
+              while (*p && !IS_DIRECTORY_SEP (*p)) p++;
+              *p = 0;
+            }
+          else
+#endif
+            newdir = "";
+        }
+    }
 #endif /* DOS_NT */
-  if (newdir != 0)
+
+  if (newdir)
     {
       /* Get rid of any slash at the end of newdir.  */
-      int length = strlen (newdir);
-      /* Adding `length > 1 &&' makes ~ expand into / when homedir
-         is the root dir.  People disagree about whether that is right.
-         Anyway, we can't take the risk of this change now.  */
-#ifdef DOS_NT
-      if (newdir[1] != ':' && length > 1)
-#endif
+      length = strlen (newdir);
       if (IS_DIRECTORY_SEP (newdir[length - 1]))
         {
           unsigned char *temp = (unsigned char *) alloca (length);
@@ -1096,7 +1272,7 @@ See also the function `substitute-in-file-name'.")
   /* Now concatenate the directory and name to new space in the stack frame */
   tlen += strlen (nm) + 1;
 #ifdef DOS_NT
-  /* Add reserved space for drive name.  (The Microsoft x86 compiler 
+  /* Add reserved space for drive name.  (The Microsoft x86 compiler
      produces incorrect code if the following two lines are combined.)  */
   target = (unsigned char *) alloca (tlen + 2);
   target += 2;
@@ -1121,6 +1297,8 @@ See also the function `substitute-in-file-name'.")
     strcpy (target, sys_translate_unix (target));
 #endif /* VMS */
 
+  /* ASSERT (IS_DIRECTORY_SEP (target[0])) if not VMS */
+
   /* Now canonicalize by removing /. and /foo/.. if they appear.  */
 
   p = target;
@@ -1176,10 +1354,10 @@ See also the function `substitute-in-file-name'.")
         }
       else if (IS_DIRECTORY_SEP (p[0]) && IS_DIRECTORY_SEP (p[1])
 #if defined (APOLLO) || defined (WINDOWSNT)
-               /* // at start of filename is meaningful in Apollo 
+               /* // at start of filename is meaningful in Apollo
                   and WindowsNT systems */
                && o != target
-#endif /* APOLLO */
+#endif /* APOLLO || WINDOWSNT */
                )
         {
           o = target;
@@ -1203,14 +1381,6 @@ See also the function `substitute-in-file-name'.")
         {
           while (o != target && (--o) && !IS_DIRECTORY_SEP (*o))
             ;
-#if defined (APOLLO) || defined (WINDOWSNT)
-          if (o == target + 1 
-              && IS_DIRECTORY_SEP (o[-1]) && IS_DIRECTORY_SEP (o[0]))
-            ++o;
-          else
-#endif /* APOLLO || WINDOWSNT */
-          if (o == target && IS_ANY_SEP (*o))
-            ++o;
           p += 3;
         }
       else
@@ -1221,18 +1391,18 @@ See also the function `substitute-in-file-name'.")
     }
 
 #ifdef DOS_NT
-  /* at last, set drive name. */
-  if (target[1] != ':'
+  /* At last, set drive name. */
 #ifdef WINDOWSNT
-      /* Allow network paths that look like "\\foo" */
-      && !(IS_DIRECTORY_SEP (target[0]) && IS_DIRECTORY_SEP (target[1]))
+  /* Except for network file name.  */
+  if (!(IS_DIRECTORY_SEP (target[0]) && IS_DIRECTORY_SEP (target[1])))
 #endif /* WINDOWSNT */
-      )
     {
+      if (!drive) abort ();
       target -= 2;
-      target[0] = (drive < 0 ? getdisk () + 'A' : drive);
+      target[0] = drive;
       target[1] = ':';
     }
+  CORRECT_DIR_SEPS (target);
 #endif /* DOS_NT */
 
   return make_string (target, o - target);
@@ -1252,7 +1422,7 @@ See also the function `substitute-in-file-name'.")
      Lisp_Object name, defalt;
 {
   unsigned char *nm;
-  
+
   register unsigned char *newdir, *p, *o;
   int tlen;
   unsigned char *target;
@@ -1266,7 +1436,7 @@ See also the function `substitute-in-file-name'.")
   int lbrack = 0, rbrack = 0;
   int dots = 0;
 #endif /* VMS */
-  
+
   CHECK_STRING (name, 0);
 
 #ifdef VMS
@@ -1275,7 +1445,7 @@ See also the function `substitute-in-file-name'.")
 #endif
 
   nm = XSTRING (name)->data;
-  
+
   /* If nm is absolute, flush ...// and detect /./ and /../.
      If no /./ or /../ we can return right away. */
   if (
@@ -1351,13 +1521,13 @@ See also the function `substitute-in-file-name'.")
                 nm = brack + 1;
                 brack = 0;
               }
-            /* if /pathname/dev:, move nm to dev: */
+            /* If /name/dev:, move nm to dev: */
             else if (slash)
               nm = slash + 1;
-            /* if node::dev:, move colon following dev */
+            /* If node::dev:, move colon following dev */
             else if (colon && colon[-1] == ':')
               colon = p;
-            /* if dev1:dev2:, move nm to dev2: */
+            /* If dev1:dev2:, move nm to dev2: */
             else if (colon && colon[-1] != ':')
               {
                 nm = colon + 1;
@@ -1593,9 +1763,10 @@ duplicates what `expand-file-name' does.")
     return call2 (handler, Qsubstitute_in_file_name, filename);
 
   nm = XSTRING (filename)->data;
-#ifdef MSDOS
-  dostounix_filename (nm = strcpy (alloca (strlen (nm) + 1), nm));
-  substituted = !strcmp (nm, XSTRING (filename)->data);
+#ifdef DOS_NT
+  nm = strcpy (alloca (strlen (nm) + 1), nm);
+  CORRECT_DIR_SEPS (nm);
+  substituted = (strcmp (nm, XSTRING (filename)->data) != 0);
 #endif
   endp = nm + XSTRING (filename)->size;
 
@@ -1603,17 +1774,14 @@ duplicates what `expand-file-name' does.")
 
   for (p = nm; p != endp; p++)
     {
-      if ((p[0] == '~' ||
-#ifdef APOLLO
-           /* // at start of file name is meaningful in Apollo system */
-           (p[0] == '/' && p - 1 != nm)
-#else /* not APOLLO */
-#ifdef WINDOWSNT
-           (IS_DIRECTORY_SEP (p[0]) && p - 1 != nm)
-#else /* not WINDOWSNT */
-           p[0] == '/'
-#endif /* not WINDOWSNT */
-#endif /* not APOLLO */
+      if ((p[0] == '~'
+#if defined (APOLLO) || defined (WINDOWSNT)
+           /* // at start of file name is meaningful in Apollo and
+              WindowsNT systems */
+           || (IS_DIRECTORY_SEP (p[0]) && p - 1 != nm)
+#else /* not (APOLLO || WINDOWSNT) */
+           || IS_DIRECTORY_SEP (p[0])
+#endif /* not (APOLLO || WINDOWSNT) */
            )
           && p != nm
           && (0
@@ -1626,7 +1794,9 @@ duplicates what `expand-file-name' does.")
           substituted = 1;
         }
 #ifdef DOS_NT
-      if (p[0] && p[1] == ':')
+      /* see comment in expand-file-name about drive specifiers */
+      else if (IS_DRIVE (p[0]) && p[1] == ':'
+               && p > nm && IS_DIRECTORY_SEP (p[-1]))
         {
           nm = p;
           substituted = 1;
@@ -1745,22 +1915,18 @@ duplicates what `expand-file-name' does.")
 
   for (p = xnm; p != x; p++)
     if ((p[0] == '~'
-#ifdef APOLLO
-         /* // at start of file name is meaningful in Apollo system */
-         || (p[0] == '/' && p - 1 != xnm)
-#else /* not APOLLO */
-#ifdef WINDOWSNT
+#if defined (APOLLO) || defined (WINDOWSNT)
          || (IS_DIRECTORY_SEP (p[0]) && p - 1 != xnm)
-#else /* not WINDOWSNT */
-         || p[0] == '/'
-#endif /* not WINDOWSNT */
-#endif /* not APOLLO */
+#else /* not (APOLLO || WINDOWSNT) */
+         || IS_DIRECTORY_SEP (p[0])
+#endif /* not (APOLLO || WINDOWSNT) */
          )
         && p != nm && IS_DIRECTORY_SEP (p[-1]))
       xnm = p;
 #ifdef DOS_NT
-    else if (p[0] && p[1] == ':')
-        xnm = p;
+    else if (IS_DRIVE (p[0]) && p[1] == ':'
+             && p > nm && IS_DIRECTORY_SEP (p[-1]))
+      xnm = p;
 #endif
 
   return make_string (xnm, x - xnm);
@@ -1783,25 +1949,25 @@ Lisp_Object
 expand_and_dir_to_file (filename, defdir)
      Lisp_Object filename, defdir;
 {
-  register Lisp_Object abspath;
+  register Lisp_Object absname;
 
-  abspath = Fexpand_file_name (filename, defdir);
+  absname = Fexpand_file_name (filename, defdir);
 #ifdef VMS
   {
-    register int c = XSTRING (abspath)->data[XSTRING (abspath)->size - 1];
+    register int c = XSTRING (absname)->data[XSTRING (absname)->size - 1];
     if (c == ':' || c == ']' || c == '>')
-      abspath = Fdirectory_file_name (abspath);
+      absname = Fdirectory_file_name (absname);
   }
 #else
-  /* Remove final slash, if any (unless path is root).
+  /* Remove final slash, if any (unless this is the root dir).
      stat behaves differently depending!  */
-  if (XSTRING (abspath)->size > 1
-      && IS_DIRECTORY_SEP (XSTRING (abspath)->data[XSTRING (abspath)->size - 1])
-      && !IS_DEVICE_SEP (XSTRING (abspath)->data[XSTRING (abspath)->size-2]))
+  if (XSTRING (absname)->size > 1
+      && IS_DIRECTORY_SEP (XSTRING (absname)->data[XSTRING (absname)->size - 1])
+      && !IS_DEVICE_SEP (XSTRING (absname)->data[XSTRING (absname)->size-2]))
     /* We cannot take shortcuts; they might be wrong for magic file names.  */
-    abspath = Fdirectory_file_name (abspath);
+    absname = Fdirectory_file_name (absname);
 #endif
-  return abspath;
+  return absname;
 }
 
 /* Signal an error if the file ABSNAME already exists.
@@ -1904,7 +2070,7 @@ A prefix arg makes KEEP-TIME non-nil.")
      copyable by us. */
   input_file_statable_p = (fstat (ifd, &st) >= 0);
 
-#ifndef DOS_NT
+#ifndef MSDOS
   if (out_st.st_mode != 0
       && st.st_dev == out_st.st_dev && st.st_ino == out_st.st_ino)
     {
@@ -2308,10 +2474,10 @@ DEFUN ("sysnetunam", Fsysnetunam, Ssysnetunam, 2, 2, 0,
      Lisp_Object path, login;
 {
   int netresult;
-  
+
   CHECK_STRING (path, 0);
-  CHECK_STRING (login, 0);  
-  
+  CHECK_STRING (login, 0);
+
   netresult = netunam (XSTRING (path)->data, XSTRING (login)->data);
 
   if (netresult == -1)
@@ -2323,7 +2489,7 @@ DEFUN ("sysnetunam", Fsysnetunam, Ssysnetunam, 2, 2, 0,
 
 DEFUN ("file-name-absolute-p", Ffile_name_absolute_p, Sfile_name_absolute_p,
        1, 1, 0,
-       "Return t if file FILENAME specifies an absolute path name.\n\
+       "Return t if file FILENAME specifies an absolute file name.\n\
 On Unix, this is a name starting with a `/' or a `~'.")
      (filename)
      Lisp_Object filename;
@@ -2340,7 +2506,7 @@ On Unix, this is a name starting with a `/' or a `~'.")
           && ptr[1] != '.')
 #endif /* VMS */
 #ifdef DOS_NT
-      || (*ptr != 0 && ptr[1] == ':' && (ptr[2] == '/' || ptr[2] == '\\'))
+      || (IS_DRIVE (*ptr) && ptr[1] == ':' && IS_DIRECTORY_SEP (ptr[2]))
 #endif
       )
     return Qt;
@@ -2360,12 +2526,16 @@ check_executable (filename)
   struct stat st;
   if (stat (filename, &st) < 0)
     return 0;
+#ifdef WINDOWSNT
+  return ((st.st_mode & S_IEXEC) != 0);
+#else
   return (S_ISREG (st.st_mode)
           && len >= 5
           && (stricmp ((suffix = filename + len-4), ".com") == 0
               || stricmp (suffix, ".exe") == 0
               || stricmp (suffix, ".bat") == 0)
           || (st.st_mode & S_IFMT) == S_IFDIR);
+#endif /* not WINDOWSNT */
 #else /* not DOS_NT */
 #ifdef HAVE_EACCESS
   return (eaccess (filename, 1) >= 0);
@@ -2409,20 +2579,20 @@ See also `file-readable-p' and `file-attributes'.")
   (filename)
      Lisp_Object filename;
 {
-  Lisp_Object abspath;
+  Lisp_Object absname;
   Lisp_Object handler;
   struct stat statbuf;
 
   CHECK_STRING (filename, 0);
-  abspath = Fexpand_file_name (filename, Qnil);
+  absname = Fexpand_file_name (filename, Qnil);
 
   /* If the file name has special constructs in it,
      call the corresponding file handler.  */
-  handler = Ffind_file_name_handler (abspath, Qfile_exists_p);
+  handler = Ffind_file_name_handler (absname, Qfile_exists_p);
   if (!NILP (handler))
-    return call2 (handler, Qfile_exists_p, abspath);
+    return call2 (handler, Qfile_exists_p, absname);
 
-  return (stat (XSTRING (abspath)->data, &statbuf) >= 0) ? Qt : Qnil;
+  return (stat (XSTRING (absname)->data, &statbuf) >= 0) ? Qt : Qnil;
 }
 
 DEFUN ("file-executable-p", Ffile_executable_p, Sfile_executable_p, 1, 1, 0,
@@ -2432,19 +2602,19 @@ For a directory, this means you can access files in that directory.")
     Lisp_Object filename;
 
 {
-  Lisp_Object abspath;
+  Lisp_Object absname;
   Lisp_Object handler;
 
   CHECK_STRING (filename, 0);
-  abspath = Fexpand_file_name (filename, Qnil);
+  absname = Fexpand_file_name (filename, Qnil);
 
   /* If the file name has special constructs in it,
      call the corresponding file handler.  */
-  handler = Ffind_file_name_handler (abspath, Qfile_executable_p);
+  handler = Ffind_file_name_handler (absname, Qfile_executable_p);
   if (!NILP (handler))
-    return call2 (handler, Qfile_executable_p, abspath);
+    return call2 (handler, Qfile_executable_p, absname);
 
-  return (check_executable (XSTRING (abspath)->data) ? Qt : Qnil);
+  return (check_executable (XSTRING (absname)->data) ? Qt : Qnil);
 }
 
 DEFUN ("file-readable-p", Ffile_readable_p, Sfile_readable_p, 1, 1, 0,
@@ -2453,32 +2623,31 @@ See also `file-exists-p' and `file-attributes'.")
   (filename)
      Lisp_Object filename;
 {
-  Lisp_Object abspath;
+  Lisp_Object absname;
   Lisp_Object handler;
   int desc;
 
   CHECK_STRING (filename, 0);
-  abspath = Fexpand_file_name (filename, Qnil);
+  absname = Fexpand_file_name (filename, Qnil);
 
   /* If the file name has special constructs in it,
      call the corresponding file handler.  */
-  handler = Ffind_file_name_handler (abspath, Qfile_readable_p);
+  handler = Ffind_file_name_handler (absname, Qfile_readable_p);
   if (!NILP (handler))
-    return call2 (handler, Qfile_readable_p, abspath);
+    return call2 (handler, Qfile_readable_p, absname);
 
-#ifdef MSDOS
-  /* Under MS-DOS, open does not work't right, because it doesn't work for
-     directories (MS-DOS won't let you open a directory).  */
-  if (access (XSTRING (abspath)->data, 0) == 0)
+#ifdef DOS_NT
+  /* Under MS-DOS and Windows, open does not work for directories.  */
+  if (access (XSTRING (absname)->data, 0) == 0)
     return Qt;
   return Qnil;
-#else /* not MSDOS */
-  desc = open (XSTRING (abspath)->data, O_RDONLY);
+#else /* not DOS_NT */
+  desc = open (XSTRING (absname)->data, O_RDONLY);
   if (desc < 0)
     return Qnil;
   close (desc);
   return Qt;
-#endif /* not MSDOS */
+#endif /* not DOS_NT */
 }
 
 /* Having this before file-symlink-p mysteriously caused it to be forgotten
@@ -2488,23 +2657,23 @@ DEFUN ("file-writable-p", Ffile_writable_p, Sfile_writable_p, 1, 1, 0,
   (filename)
      Lisp_Object filename;
 {
-  Lisp_Object abspath, dir;
+  Lisp_Object absname, dir;
   Lisp_Object handler;
   struct stat statbuf;
 
   CHECK_STRING (filename, 0);
-  abspath = Fexpand_file_name (filename, Qnil);
+  absname = Fexpand_file_name (filename, Qnil);
 
   /* If the file name has special constructs in it,
      call the corresponding file handler.  */
-  handler = Ffind_file_name_handler (abspath, Qfile_writable_p);
+  handler = Ffind_file_name_handler (absname, Qfile_writable_p);
   if (!NILP (handler))
-    return call2 (handler, Qfile_writable_p, abspath);
+    return call2 (handler, Qfile_writable_p, absname);
 
-  if (stat (XSTRING (abspath)->data, &statbuf) >= 0)
-    return (check_writable (XSTRING (abspath)->data)
+  if (stat (XSTRING (absname)->data, &statbuf) >= 0)
+    return (check_writable (XSTRING (absname)->data)
             ? Qt : Qnil);
-  dir = Ffile_name_directory (abspath);
+  dir = Ffile_name_directory (absname);
 #ifdef VMS
   if (!NILP (dir))
     dir = Fdirectory_file_name (dir);
@@ -2571,19 +2740,19 @@ if the directory so specified exists and really is a directory.")
   (filename)
      Lisp_Object filename;
 {
-  register Lisp_Object abspath;
+  register Lisp_Object absname;
   struct stat st;
   Lisp_Object handler;
 
-  abspath = expand_and_dir_to_file (filename, current_buffer->directory);
+  absname = expand_and_dir_to_file (filename, current_buffer->directory);
 
   /* If the file name has special constructs in it,
      call the corresponding file handler.  */
-  handler = Ffind_file_name_handler (abspath, Qfile_directory_p);
+  handler = Ffind_file_name_handler (absname, Qfile_directory_p);
   if (!NILP (handler))
-    return call2 (handler, Qfile_directory_p, abspath);
+    return call2 (handler, Qfile_directory_p, absname);
 
-  if (stat (XSTRING (abspath)->data, &st) < 0)
+  if (stat (XSTRING (absname)->data, &st) < 0)
     return Qnil;
   return (st.st_mode & S_IFMT) == S_IFDIR ? Qt : Qnil;
 }
@@ -2627,19 +2796,19 @@ This is the sort of file that holds an ordinary stream of data bytes.")
   (filename)
      Lisp_Object filename;
 {
-  register Lisp_Object abspath;
+  register Lisp_Object absname;
   struct stat st;
   Lisp_Object handler;
 
-  abspath = expand_and_dir_to_file (filename, current_buffer->directory);
+  absname = expand_and_dir_to_file (filename, current_buffer->directory);
 
   /* If the file name has special constructs in it,
      call the corresponding file handler.  */
-  handler = Ffind_file_name_handler (abspath, Qfile_regular_p);
+  handler = Ffind_file_name_handler (absname, Qfile_regular_p);
   if (!NILP (handler))
-    return call2 (handler, Qfile_regular_p, abspath);
+    return call2 (handler, Qfile_regular_p, absname);
 
-  if (stat (XSTRING (abspath)->data, &st) < 0)
+  if (stat (XSTRING (absname)->data, &st) < 0)
     return Qnil;
   return (st.st_mode & S_IFMT) == S_IFREG ? Qt : Qnil;
 }
@@ -2649,24 +2818,24 @@ DEFUN ("file-modes", Ffile_modes, Sfile_modes, 1, 1, 0,
   (filename)
      Lisp_Object filename;
 {
-  Lisp_Object abspath;
+  Lisp_Object absname;
   struct stat st;
   Lisp_Object handler;
 
-  abspath = expand_and_dir_to_file (filename, current_buffer->directory);
+  absname = expand_and_dir_to_file (filename, current_buffer->directory);
 
   /* If the file name has special constructs in it,
      call the corresponding file handler.  */
-  handler = Ffind_file_name_handler (abspath, Qfile_modes);
+  handler = Ffind_file_name_handler (absname, Qfile_modes);
   if (!NILP (handler))
-    return call2 (handler, Qfile_modes, abspath);
+    return call2 (handler, Qfile_modes, absname);
 
-  if (stat (XSTRING (abspath)->data, &st) < 0)
+  if (stat (XSTRING (absname)->data, &st) < 0)
     return Qnil;
-#ifdef DOS_NT
-  if (check_executable (XSTRING (abspath)->data))
+#ifdef MSDOS
+  if (check_executable (XSTRING (absname)->data))
     st.st_mode |= S_IEXEC;
-#endif /* DOS_NT */
+#endif /* MSDOS */
 
   return make_number (st.st_mode & 07777);
 }
@@ -2677,20 +2846,20 @@ Only the 12 low bits of MODE are used.")
   (filename, mode)
      Lisp_Object filename, mode;
 {
-  Lisp_Object abspath;
+  Lisp_Object absname;
   Lisp_Object handler;
 
-  abspath = Fexpand_file_name (filename, current_buffer->directory);
+  absname = Fexpand_file_name (filename, current_buffer->directory);
   CHECK_NUMBER (mode, 1);
 
   /* If the file name has special constructs in it,
      call the corresponding file handler.  */
-  handler = Ffind_file_name_handler (abspath, Qset_file_modes);
+  handler = Ffind_file_name_handler (absname, Qset_file_modes);
   if (!NILP (handler))
-    return call3 (handler, Qset_file_modes, abspath, mode);
+    return call3 (handler, Qset_file_modes, absname, mode);
 
-  if (chmod (XSTRING (abspath)->data, XINT (mode)) < 0)
-    report_file_error ("Doing chmod", Fcons (abspath, Qnil));
+  if (chmod (XSTRING (absname)->data, XINT (mode)) < 0)
+    report_file_error ("Doing chmod", Fcons (absname, Qnil));
 
   return Qnil;
 }
@@ -2703,7 +2872,7 @@ This setting is inherited by subprocesses.")
      Lisp_Object mode;
 {
   CHECK_NUMBER (mode, 0);
-  
+
   umask ((~ XINT (mode)) & 0777);
 
   return Qnil;
@@ -2743,7 +2912,7 @@ otherwise, if FILE2 does not exist, the answer is t.")
   (file1, file2)
      Lisp_Object file1, file2;
 {
-  Lisp_Object abspath1, abspath2;
+  Lisp_Object absname1, absname2;
   struct stat st;
   int mtime1;
   Lisp_Object handler;
@@ -2752,26 +2921,26 @@ otherwise, if FILE2 does not exist, the answer is t.")
   CHECK_STRING (file1, 0);
   CHECK_STRING (file2, 0);
 
-  abspath1 = Qnil;
-  GCPRO2 (abspath1, file2);
-  abspath1 = expand_and_dir_to_file (file1, current_buffer->directory);
-  abspath2 = expand_and_dir_to_file (file2, current_buffer->directory);
+  absname1 = Qnil;
+  GCPRO2 (absname1, file2);
+  absname1 = expand_and_dir_to_file (file1, current_buffer->directory);
+  absname2 = expand_and_dir_to_file (file2, current_buffer->directory);
   UNGCPRO;
 
   /* If the file name has special constructs in it,
      call the corresponding file handler.  */
-  handler = Ffind_file_name_handler (abspath1, Qfile_newer_than_file_p);
+  handler = Ffind_file_name_handler (absname1, Qfile_newer_than_file_p);
   if (NILP (handler))
-    handler = Ffind_file_name_handler (abspath2, Qfile_newer_than_file_p);
+    handler = Ffind_file_name_handler (absname2, Qfile_newer_than_file_p);
   if (!NILP (handler))
-    return call3 (handler, Qfile_newer_than_file_p, abspath1, abspath2);
+    return call3 (handler, Qfile_newer_than_file_p, absname1, absname2);
 
-  if (stat (XSTRING (abspath1)->data, &st) < 0)
+  if (stat (XSTRING (absname1)->data, &st) < 0)
     return Qnil;
 
   mtime1 = st.st_mtime;
 
-  if (stat (XSTRING (abspath2)->data, &st) < 0)
+  if (stat (XSTRING (absname2)->data, &st) < 0)
     return Qt;
 
   return (mtime1 > st.st_mtime) ? Qt : Qnil;
@@ -3148,7 +3317,7 @@ and (2) it puts less data in the undo list.")
   /* Decode file format */
   if (inserted > 0)
     {
-      insval = call3 (Qformat_decode, 
+      insval = call3 (Qformat_decode,
                       Qnil, make_number (inserted), visit);
       CHECK_NUMBER (insval, 0);
       inserted = XFASTINT (insval);
@@ -3156,7 +3325,7 @@ and (2) it puts less data in the undo list.")
 
   if (inserted > 0 && NILP (visit) && total > 0)
     signal_after_change (point, 0, inserted);
-  
+
   if (inserted > 0)
     {
       p = Vafter_insert_file_functions;
@@ -3186,7 +3355,7 @@ static Lisp_Object build_annotations ();
 /* If build_annotations switched buffers, switch back to BUF.
    Kill the temporary buffer that was selected in the meantime.  */
 
-static Lisp_Object 
+static Lisp_Object
 build_annotations_unwind (buf)
      Lisp_Object buf;
 {
@@ -3273,7 +3442,7 @@ to the file, instead of any buffer contents, and END is ignored.")
   handler = Ffind_file_name_handler (filename, Qwrite_region);
   /* If FILENAME has no handler, see if VISIT has one.  */
   if (NILP (handler) && STRINGP (visit))
-    handler = Ffind_file_name_handler (visit, Qwrite_region);    
+    handler = Ffind_file_name_handler (visit, Qwrite_region);
 
   if (!NILP (handler))
     {
@@ -3371,8 +3540,8 @@ to the file, instead of any buffer contents, and END is ignored.")
       }
 #else /* not VMS */
 #ifdef DOS_NT
-  desc = open (fn, 
-               O_WRONLY | O_TRUNC | O_CREAT | buffer_file_type, 
+  desc = open (fn,
+               O_WRONLY | O_TRUNC | O_CREAT | buffer_file_type,
                S_IREAD | S_IWRITE);
 #else  /* not DOS_NT */
   desc = creat (fn, auto_saving ? auto_save_mode_bits : 0666);
@@ -3476,7 +3645,7 @@ to the file, instead of any buffer contents, and END is ignored.")
     }
 #endif
 
-  /* Spurious "file has changed on disk" warnings have been 
+  /* Spurious "file has changed on disk" warnings have been
      observed on Suns as well.
      It seems that `close' can change the modtime, under nfs.
 
@@ -3882,7 +4051,7 @@ A non-nil CURRENT-ONLY argument means save only current buffer.")
       Lisp_Object listfile;
       listfile = Fexpand_file_name (Vauto_save_list_file_name, Qnil);
 #ifdef DOS_NT
-      listdesc = open (XSTRING (listfile)->data, 
+      listdesc = open (XSTRING (listfile)->data,
                        O_WRONLY | O_TRUNC | O_CREAT | O_TEXT,
                        S_IREAD | S_IWRITE);
 #else  /* not DOS_NT */
@@ -3891,7 +4060,7 @@ A non-nil CURRENT-ONLY argument means save only current buffer.")
     }
   else
     listdesc = -1;
-  
+
   /* Arrange to close that file whether or not we get an error.
      Also reset auto_saving to 0.  */
   record_unwind_protect (do_auto_save_unwind, make_number (listdesc));
@@ -3908,7 +4077,7 @@ A non-nil CURRENT-ONLY argument means save only current buffer.")
       {
         buf = XCONS (XCONS (tail)->car)->cdr;
         b = XBUFFER (buf);
-      
+
         /* Record all the buffers that have auto save mode
            in the special file that lists them.  For each of these buffers,
            Record visited name (if any) and auto save name.  */
@@ -4179,6 +4348,10 @@ DIR defaults to current buffer's directory default.")
 
   /* If dir starts with user's homedir, change that to ~. */
   homedir = (char *) egetenv ("HOME");
+#ifdef DOS_NT
+  homedir = strcpy (alloca (strlen (homedir) + 1), homedir);
+  CORRECT_DIR_SEPS (homedir);
+#endif
   if (homedir != 0
       && STRINGP (dir)
       && !strncmp (homedir, XSTRING (dir)->data, strlen (homedir))
@@ -4372,7 +4545,7 @@ syms_of_fileio ()
 
   Qfile_error = intern ("file-error");
   staticpro (&Qfile_error);
-  Qfile_already_exists = intern("file-already-exists");
+  Qfile_already_exists = intern ("file-already-exists");
   staticpro (&Qfile_already_exists);
 
 #ifdef DOS_NT
@@ -4415,6 +4588,14 @@ same format as a regular save would use.");
 nil means use format `var'.  This variable is meaningful only on VMS.");
   vms_stmlf_recfm = 0;
 
+  DEFVAR_LISP ("directory-sep-char", &Vdirectory_sep_char,
+    "Directory separator character for built-in functions that return file names.\n\
+The value should be either ?/ or ?\\ (any other value is treated as ?\\).\n\
+This variable affects the built-in functions only on Windows,\n\
+on other platforms, it is initialized so that Lisp code can find out\n\
+what the normal separator is.");
+  Vdirectory_sep_char = '/';
+
   DEFVAR_LISP ("file-name-handler-alist", &Vfile_name_handler_alist,
     "*Alist of elements (REGEXP . HANDLER) for file names handled specially.\n\
 If a file name matches REGEXP, then all I/O on that file is done by calling\n\