sbrklnx.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 75 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
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*    provided with the Original Code and Modifications, and is also
*    available at www.sybase.com/developer/opensource.
*
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* Description:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
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****************************************************************************/


#include "dll.h"        // needs to be first
#include "variety.h"
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <unistd.h>
#include "syslinux.h"
#include "heapacc.h"
#include "heap.h"

_WCRTLINK void _WCNEAR *sbrk( int increment ) {
    return( __brk( _curbrk + increment ) );
}

_WCRTLINK int brk( void *endds ) {
    return( __brk( (unsigned) endds ) == (void *)-1 ? -1 : 0 );
}

_WCRTLINK void _WCNEAR *__brk( unsigned brk_value )
{
    unsigned old_brk_value;
    unsigned sys_brk_value;
    
    /* try setting the block of memory */
    _AccessNHeap();

    sys_brk_value = sys_brk( brk_value );
    if( sys_brk_value == -1 ) {
        errno = ENOMEM;
        _ReleaseNHeap();
        return( (void _WCNEAR *) -1 );
    }
    if ( _curbrk == 0 ) {
        _curbrk = brk_value = sys_brk_value;
    }
    
    old_brk_value = _curbrk;        /* return old value of _curbrk */
    _curbrk = brk_value;            /* set new break value */
    
    _ReleaseNHeap();
    return( (void _WCNEAR *) old_brk_value );
}