seekunit.c

来自「开放源码的编译器open watcom 1.6.0版的源代码」· C语言 代码 · 共 70 行

/****************************************************************************
*
*                            Open Watcom Project
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*    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
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*  ========================================================================
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*    This file contains Original Code and/or Modifications of Original
*    Code as defined in and that are subject to the Sybase Open Watcom
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* Description:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
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//
// SEEKUNIT     : seek to offset in sequential access file
//

#include "ftnstd.h"
#include "rundat.h"
#include "fio.h"

#include <stddef.h>

extern  int             SysSeek(b_file *,long int,int);
extern  long int        FGetFilePos(b_file *);


intstar4        fortran SEEKUNIT( intstar4 *unit, intstar4 *offset,
                                  intstar4 *origin ) {
//====================================================

    ftnfile     *fcb;

    fcb = Files;
    for(;;) {
        if( fcb == NULL ) return( -1 );
        if( *unit == fcb->unitid ) {
            if( fcb->fileptr == NULL ) return( -1 );
            if( _NoRecordOrganization( fcb ) ) {
                if( SysSeek( fcb->fileptr, *offset, *origin ) == -1 ) {
                    return( -1 );
                } else {
                    return( FGetFilePos( fcb->fileptr ) );
                }
            }
            return( -1 );
        }
        fcb = fcb->link;
    }
}