[gfortran] Stop rewind deleting files.

[Paul Brook <paul at codesourcery dot com>]

A write to a sequential assess file followed by tow rewind statements would 
truncate the file to zero length.The fix seems to be to put the unit into 
read mode after a rewind statement.

Tested on i686-linux.
Applied to mainline.

Paul

2004-08-27  Paul Brook  <paul@codesourcery.com>

	* io/rewind.c (st_rewind): Reset unit to read mode.
testsuite/
	* gfortran.dg/rewind_1.f90: New test.

Index: rewind.c
===================================================================
RCS file: /var/cvsroot/gcc-cvs/gcc/libgfortran/io/rewind.c,v
retrieving revision 1.4
diff -u -p -r1.4 rewind.c
--- rewind.c	27 Aug 2004 07:59:30 -0000	1.4
+++ rewind.c	27 Aug 2004 13:24:21 -0000
@@ -40,8 +40,13 @@ st_rewind (void)
 			"Cannot REWIND a file opened for DIRECT access");
       else
 	{
+	  /* If we have been writing to the file, the last written record
+	     is the last record in the file, so trincate the file now.
+	     Reset to read mode so two consecutive rewind statements
+	     don't delete the file contents.  */
           if (u->mode==WRITING)
             struncate(u->s);
+	  u->mode = READING;
 	  u->last_record = 0;
 	  if (sseek (u->s, 0) == FAILURE)
 	    generate_error (ERROR_OS, NULL);

Attachment: rewind_1.f90
Description: Text document