libgfortran/io/rewind.c

   1
   2 /* Copyright (C) 2002-2003 Free Software Foundation, Inc.
   3    Contributed by Andy Vaught
   4
   5 This file is part of the GNU Fortran 95 runtime library (libgfortran).
   6
   7 Libgfortran is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 Libgfortran is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with Libgfortran; see the file COPYING.  If not, write to
  19 the Free Software Foundation, 59 Temple Place - Suite 330,
  20 Boston, MA 02111-1307, USA.  */
  21
  22 #include "config.h"
  23 #include "libgfortran.h"
  24 #include "io.h"
  25
  26 /* rewind.c--  Implement the rewind statement */
  27
  28 void
  29 st_rewind (void)
  30 {
  31   gfc_unit *u;
  32
  33   library_start ();
  34
  35   u = find_unit (ioparm.unit);
  36   if (u != NULL)
  37     {
  38       if (u->flags.access != ACCESS_SEQUENTIAL)
  39         generate_error (ERROR_BAD_OPTION,
  40                         "Cannot REWIND a file opened for DIRECT access");
  41       else
  42         {
  43           if (u->mode==WRITING)
  44             struncate(u->s);
  45           u->last_record = 0;
  46           if (sseek (u->s, 0) == FAILURE)
  47             generate_error (ERROR_OS, NULL);
  48
  49           u->endfile = NO_ENDFILE;
  50           u->current_record = 0;
  51           test_endfile (u);
  52         }
  53     }
  54
  55   library_end ();
  56 }