impopen.c

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/*

  Copyright (C) 2000, 2001, Silicon Graphics, Inc.  All Rights Reserved.

  This program is free software; you can redistribute it and/or modify it
  under the terms of version 2.1 of the GNU Lesser General Public License 
  as published by the Free Software Foundation.

  This program is distributed in the hope that it would be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  

  Further, this software is distributed without any warranty that it is
  free of the rightful claim of any third person regarding infringement 
  or the like.  Any license provided herein, whether implied or 
  otherwise, applies only to this software file.  Patent licenses, if
  any, provided herein do not apply to combinations of this program with 
  other software, or any other product whatsoever.  

  You should have received a copy of the GNU Lesser General Public 
  License along with this program; if not, write the Free Software 
  Foundation, Inc., 59 Temple Place - Suite 330, Boston MA 02111-1307, 
  USA.

  Contact information:  Silicon Graphics, Inc., 1600 Amphitheatre Pky,
  Mountain View, CA 94043, or:

  http://www.sgi.com

  For further information regarding this notice, see:

  http://oss.sgi.com/projects/GenInfo/NoticeExplan

*/



#pragma ident "@(#) libf/fio/impopen.c  92.1    06/21/99 10:37:55"

#include <cray/nassert.h>
#include "fio.h"

/*
 * _ll_implicit_open
 * _imp_open
 * _imp_open77
 *
 *              Performs an implicit open for a unit which was not mentioned
 *              in an OPEN statement before its first I/O (Cray extension).
 *              Upon successful completion, the unit is open and locked.
 *              Since another task might sneak in and open this unit while
 *              _imp_open is being called, the unit should be validated
 *              for proper form and access in the calling routine after return
 *              from _imp_open.  
 *
 *              Side effect:
 *                      Stores its return value in css->f_cu
 *
 *              Return value:
 *                      The unit pointer on success.
 *                      NULL if error, with error status returned in *errstat.
 */

unit *
_ll_implicit_open(
        FIOSPTR css,            /* Fortran I/O statement state */
        int     acc,            /* SEQ or DIR */
        int     form,           /* FMT or UNF */
        unum_t  unum,           /* Unit number */
        int     errflag,        /* Set if error recovery */
        int     *errstat,       /* Gets error status if error recovery.
                                   May be NULL if errflag == 0 */
        int     isf90)          /* =0 iff cf77 style I/O is requested */
{
        int     errn;
        olist   a;
        unit    *cup;

        OPENLOCK();             /* prevent any other OPENs or CLOSEs now */

        errn    = 0;
        cup     = NULL;

        if (acc == DIR) {
                errn    = FECONNDA;
                goto done;
        }       
                
        if (!GOOD_UNUM(unum)) {
                errn    = FEIVUNIT;
                goto done;
        }       

        cup     = _get_cup(unum);

/*
 *      If the unit is connected, another task must have opened it while
 *      _imp_open was being called, and before _openlock was locked.
 *      Skip the open processing if the unit is already open.
 */
        if (cup == NULL) {

                a.oerr          = errflag;      /* Set error recovery    */
                a.ounit         = unum;         /* Fortran unit number   */
                a.ofile         = NULL;         /* No file name          */
                a.ofilelen      = 0;            /*    or length          */
                a.ostatus       = OS_UNKNOWN;
                a.oaccess       = OS_SEQUENTIAL;
                a.oform         = (form == FMT) ? OS_FORMATTED : OS_UNFORMATTED;
                a.orecl         = 0;
                a.oposition     = OS_ASIS;
                a.oaction       = OS_ACTION_UNSPECIFIED;
                a.oblank        = OS_NULL;
                a.odelim        = OS_NONE;
                a.opad          = OS_YES;
  
                errn    = _f_open(css, &cup, &a, isf90);        
        }

done:

        OPENUNLOCK();

        if (errn != 0) {                /* Handle an error condition */
                if (cup != NULL)
                        _release_cup(cup);

                if (errflag) {
                        *errstat        = errn;
                        return(NULL);
                }

                _ferr(css, errn, unum); /* FEIVUNIT needs unum as 2nd arg */
        }

        css->f_cu       = cup;
        return(cup);
}

/*
 *      _implicit_open will be phased out in favor of _imp_open and _imp_open77
 */
unit *
_implicit_open(int acc, int form, unum_t unum, int errflag, int *errstat)
{
        FIOSPTR css;
        GET_FIOS_PTR(css);
        return(_ll_implicit_open(css, acc, form, unum, errflag, errstat, 1) );
}

/*
 *      _imp_open implicitly opens a unit which by default uses Fortran 90
 *      style formatted I/O.
 */ 
unit *
_imp_open(FIOSPTR css, int acc, int form, unum_t unum, int errflag,
          int *errstat)
{
        return(_ll_implicit_open(css, acc, form, unum, errflag, errstat, 1) );
}

/*
 *      _imp_open77 implicitly opens a unit which by default uses cf77
 *      style formatted I/O.
 */ 
unit *
_imp_open77(FIOSPTR css, int acc, int form, unum_t unum, int errflag,
            int *errstat)
{
        return(_ll_implicit_open(css, acc, form, unum, errflag, errstat, 0) );
}