re PR libfortran/31052 ([4.2 only] Bad IOSTAT values when readings NAMELISTs past EOF)

2007-03-18  Jerry DeLisle  <jvdelisle@gcc.gnu.org>

	PR libgfortran/31052
	* io/file_position (st_rewind): Fix comments. Remove use of
	test_endfile. Don't seek if already at 0 position.  Use new is_special
	function to set endfile state.
	* io/open.c (test_endfile): Delete this function.
	* io/io.h: Delete prototype for test_endfile.  Add prototype
	for is_special.
	* io/unix.c (is_special): New function. Fix whitespace.
	* io/transfer.c (next_record_r): Remove use of test_endfile.

From-SVN: r123038

libgfortran/ChangeLog

+2007-03-18  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
+
+	PR libgfortran/31052
+	* io/file_position (st_rewind): Fix comments. Remove use of
+	test_endfile. Don't seek if already at 0 position.  Use new is_special
+	function to set endfile state.
+	* io/open.c (test_endfile): Delete this function.
+	* io/io.h: Delete prototype for test_endfile.  Add prototype
+	for is_special.
+	* io/unix.c (is_special): New function. Fix whitespace.
+	* io/transfer.c (next_record_r): Remove use of test_endfile.
+
 2007-03-16  David Edelsohn  <edelsohn@gnu.org>
 
 	* runtime/main.c: Include "config.h" first.

libgfortran/io/file_pos.c

@@ -306,14 +306,27 @@ st_rewind (st_parameter_filepos *fpp)
 
 	  u->mode = READING;
 	  u->last_record = 0;
-	  if (sseek (u->s, 0) == FAILURE)
+
+	  if (file_position (u->s) != 0 && sseek (u->s, 0) == FAILURE)
 	    generate_error (&fpp->common, ERROR_OS, NULL);
 
-	  u->endfile = NO_ENDFILE;
+	  /* Handle special files like /dev/null differently.  */
+	  if (!is_special (u->s))
+	    {
+	      /* We are rewinding so we are not at the end.  */
+	      u->endfile = NO_ENDFILE;
+	    }
+	  else
+	    {
+	      /* Set this for compatibilty with g77 for /dev/null.  */
+	      if (file_length (u->s) == 0  && file_position (u->s) == 0)
+		u->endfile = AT_ENDFILE;
+	      /* Future refinements on special files can go here.  */
+	    }
+
 	  u->current_record = 0;
 	  u->strm_pos = 1;
 	  u->read_bad = 0;
-	  test_endfile (u);
 	}
       /* Update position for INQUIRE.  */
       u->flags.position = POSITION_REWIND;

libgfortran/io/io.h

@@ -622,6 +622,9 @@ internal_proto(file_position);
 extern int is_seekable (stream *);
 internal_proto(is_seekable);
 
+extern int is_special (stream *);
+internal_proto(is_special);
+
 extern int is_preconnected (stream *);
 internal_proto(is_preconnected);
 
@@ -691,9 +694,6 @@ internal_proto(unlock_unit);
 
 /* open.c */
 
-extern void test_endfile (gfc_unit *);
-internal_proto(test_endfile);
-
 extern gfc_unit *new_unit (st_parameter_open *, gfc_unit *, unit_flags *);
 internal_proto(new_unit);
 

libgfortran/io/open.c

@@ -109,19 +109,6 @@ static const st_option convert_opt[] =
   { NULL, 0}
 };
 
-/* Given a unit, test to see if the file is positioned at the terminal
-   point, and if so, change state from NO_ENDFILE flag to AT_ENDFILE.
-   This prevents us from changing the state from AFTER_ENDFILE to
-   AT_ENDFILE.  */
-
-void
-test_endfile (gfc_unit * u)
-{
-  if (u->endfile == NO_ENDFILE && file_length (u->s) == file_position (u->s))
-    u->endfile = AT_ENDFILE;
-}
-
-
 /* Change the modes of a file, those that are allowed * to be
    changed.  */
 
@@ -208,8 +195,6 @@ edit_modes (st_parameter_open *opp, gfc_unit * u, unit_flags * flags)
 
       u->current_record = 0;
       u->last_record = 0;
-
-      test_endfile (u);		/* We might be at the end.  */
       break;
 
     case POSITION_APPEND:
@@ -486,13 +471,6 @@ new_unit (st_parameter_open *opp, gfc_unit *u, unit_flags * flags)
   memmove (u->file, opp->file, opp->file_len);
   u->file_len = opp->file_len;
 
-  /* Curiously, the standard requires that the
-     position specifier be ignored for new files so a newly connected
-     file starts out that the initial point.  We still need to figure
-     out if the file is at the end or not.  */
-
-  test_endfile (u);
-
   if (flags->status == STATUS_SCRATCH && opp->file != NULL)
     free_mem (opp->file);
   return u;

libgfortran/io/transfer.c

@@ -2222,9 +2222,6 @@ next_record_r (st_parameter_dt *dtp)
 
       break;
     }
-
-  if (dtp->u.p.current_unit->flags.access == ACCESS_SEQUENTIAL)
-    test_endfile (dtp->u.p.current_unit);
 }
 
 
@@ -2684,10 +2681,7 @@ st_read (st_parameter_dt *dtp)
 
   data_transfer_init (dtp, 1);
 
-  /* Handle complications dealing with the endfile record.  It is
-     significant that this is the only place where ERROR_END is
-     generated.  Reading an end of file elsewhere is either end of
-     record or an I/O error. */
+  /* Handle complications dealing with the endfile record. */
 
   if (dtp->u.p.current_unit->flags.access == ACCESS_SEQUENTIAL)
     switch (dtp->u.p.current_unit->endfile)

libgfortran/io/unix.c

@@ -1872,7 +1872,7 @@ file_length (stream * s)
 /* file_position()-- Return the current position of the file */
 
 gfc_offset
-file_position (stream * s)
+file_position (stream *s)
 {
   return ((unix_stream *) s)->logical_offset;
 }
@@ -1882,13 +1882,22 @@ file_position (stream * s)
  * it is not */
 
 int
-is_seekable (stream * s)
+is_seekable (stream *s)
 {
   /* By convention, if file_length == -1, the file is not
      seekable.  */
   return ((unix_stream *) s)->file_length!=-1;
 }
 
+
+/* is_special()-- Return nonzero if the stream is not a regular file.  */
+
+is_special (stream *s)
+{
+  return ((unix_stream *) s)->special_file;
+}
+
+
 try
 flush (stream *s)
 {