usr/src/usr.bin/f77/libU77/fseek_.c

/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 *
 *      @(#)fseek_.c    5.1     %G%
 */

/*
 * position a file associated with a fortran logical unit
 *
 * calling sequence:
 *      ierror = fseek(lunit, ioff, ifrom)
 * where:
 *      lunit is an open logical unit
 *      ioff is an offset in bytes relative to the position specified by ifrom
 *      ifrom   - 0 means 'beginning of the file'
 *              - 1 means 'the current position'
 *              - 2 means 'the end of the file'
 *      ierror will be 0 if successful, a system error code otherwise.
 */

#include        <stdio.h>
#include        "../libI77/f_errno.h"
#include        "../libI77/fiodefs.h"

extern unit units[];

long fseek_(lu, off, from)
long *lu, *off, *from;
{
        if (*lu < 0 || *lu >= MXUNIT)
                return((long)(errno=F_ERUNIT));
        if (*from < 0 || *from > 2)
                return((long)(errno=F_ERARG));
        if (!units[*lu].ufd)
                return((long)(errno=F_ERNOPEN));
        if (fseek(units[*lu].ufd, *off, (int)*from) < 0)
                return((long)errno);
        return(0L);
}