re PR libfortran/19872 ([4.0 only] closed and re-opened file not overwriten)

PR fortran/19872
* io/transfer.c (data_transfer_init): truncate an existing
  file on the first write.

Co-Authored-By: Steven G. Kargl <kargls@comcast.net>

From-SVN: r97937

libgfortran/ChangeLog

+2005-04-09  Bud Davis  <bdavis@gfortran.org>
+            Steven G. Kargl <kargls@comcast.net>
+
+	PR fortran/19872
+	* io/transfer.c (data_transfer_init): truncate an existing
+	file on the first write.
+
 2005-04-09  Thomas Koenig  <Thomas.Koenig@online.de>
 
 	PR libfortran/19106

libgfortran/io/transfer.c

@@ -1103,6 +1103,13 @@ data_transfer_init (int read_flag)
 	generate_error (ERROR_OS, NULL);
     }
 
+  /* Overwriting an existing sequential file ? 
+     it is always safe to truncate the file on the first write */
+  if (g.mode == WRITING 
+      && current_unit->flags.access == ACCESS_SEQUENTIAL 
+      && current_unit->current_record == 0)
+        struncate(current_unit->s); 
+
   current_unit->mode = g.mode;
 
   /* Set the initial value of flags.  */