posflush.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 85 行

/****************************************************************************
*
*                            Open Watcom Project
*
*    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
*
*  ========================================================================
*
*    This file contains Original Code and/or Modifications of Original
*    Code as defined in and that are subject to the Sybase Open Watcom
*    Public License version 1.0 (the 'License'). You may not use this file
*    except in compliance with the License. BY USING THIS FILE YOU AGREE TO
*    ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
*    provided with the Original Code and Modifications, and is also
*    available at www.sybase.com/developer/opensource.
*
*    The Original Code and all software distributed under the License are
*    distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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* Description:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
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****************************************************************************/


//
// POSFLUSH     : POSIX level i/o support
//

#include "ftnstd.h"
#include "fio.h"
#include "posio.h"

extern  uint            writebytes(b_file *,char *,uint);


int     FlushBuffer( b_file *io ) {
//=================================

// Flush i/o buffer.

    uint        amt;
    int         bytes_written;
    int         rc;

    if( ( io->attrs & BUFFERED ) == 0 ) return( 0 );
    rc = 0;
    if( io->attrs & DIRTY_BUFFER ) {
        if( io->attrs & READ_AHEAD ) {
            if( lseek( io->handle, -(long)io->read_len, SEEK_CUR ) < 0 ) {
                return( -1 );
            }
            amt = io->high_water;
            if( amt < io->read_len ) {
                amt = io->read_len;
            }
            bytes_written = write( io->handle, io->buffer, amt );
            if( bytes_written < 0 ) {
                return( -1 );
            }
            io->phys_offset += bytes_written - io->read_len;
            if( bytes_written < amt ) {
                rc = -1;
            }
        } else {
            writebytes( io, &io->buffer, io->high_water );
            if( io->stat != IO_OK ) {
                rc = -1;
            }
        }
    }
    io->b_curs = 0;
    io->read_len = 0;
    io->high_water = 0;
    io->attrs &= ~(READ_AHEAD | DIRTY_BUFFER);
    return( rc );
}