libstdc++ - ios::ate not working

[Martin v. Loewis]

>  In the following program, the info in both 'Length' lines should be
>  the same (as it is in earlier libstdc++2.9 versions). However,
>  while the second line is correct, the first on always outputs 0.

Thanks for your bug report. A patch is attached below.

Ok to install in gcc mainline and release branch?

Regards,
Martin

1999-11-21  Martin v. Löwis  <loewis@informatik.hu-berlin.de>

	* filebuf.cc (open): Support ios::ate if _G_HAVE_IO_FILE_OPEN.

Index: filebuf.cc
===================================================================
RCS file: /cvs/gcc/egcs/libio/filebuf.cc,v
retrieving revision 1.3
diff -u -r1.3 filebuf.cc
--- filebuf.cc	1998/02/24 20:09:49	1.3
+++ filebuf.cc	1999/11/21 21:07:48
@@ -1,5 +1,5 @@
 /* This is part of libio/iostream, providing -*- C++ -*- input/output.
-Copyright (C) 1993, 1995 Free Software Foundation
+Copyright (C) 1993, 1995, 1999 Free Software Foundation
 
 This file is part of the GNU IO Library.  This library is free
 software; you can redistribute it and/or modify it under the
@@ -112,8 +112,16 @@
   if (mode & (int)ios::noreplace)
     posix_mode |= O_EXCL;
 #if _G_HAVE_IO_FILE_OPEN
-  return (filebuf*)_IO_file_open (this, filename, posix_mode, prot,
-				  read_write, 0);
+  if (!_IO_file_open (this, filename, posix_mode, prot, 
+		      read_write, 0))
+    return NULL;
+  if (mode & (ios::ate|ios::app)) {
+    if (pubseekoff(0, ios::end) == EOF) {
+      _IO_un_link (this);
+      return NULL;
+    }
+  }
+  return this;
 #else
   int fd = ::open(filename, posix_mode, prot);
   if (fd < 0)