clocko32.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 65 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
*    EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
*    ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
*    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
*    NON-INFRINGEMENT. Please see the License for the specific language
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*  ========================================================================
*
* Description:  32-bit OS/2 implementation of clock().
*
****************************************************************************/

#include "variety.h"
#include <time.h>
#include <rtinit.h>
#include <wos2.h>

/* OS/2 gives us time in milliseconds, so we're OK as long as
 * clock() is also expected to return milliseconds.
 */
#if CLOCKS_PER_SEC != 1000
    #error OS returned time needs adjusting!
#endif

static clock_t init_milliseconds;

/* The system millisecond counter will wrap after ~49 days. This
 * is is a) not considered a real problem and b) consistent with
 * the behaviour of IBM's C runtimes.
 */
_WCRTLINK clock_t clock( void )
{
    ULONG   milliseconds;

    DosQuerySysInfo( QSV_MS_COUNT, QSV_MS_COUNT,
                     &milliseconds, sizeof( milliseconds ) );
    return( milliseconds - init_milliseconds );
}

static void __clock_init( void )
{
    DosQuerySysInfo( QSV_MS_COUNT, QSV_MS_COUNT,
                     &init_milliseconds, sizeof( init_milliseconds ) );
}

AXI( __clock_init, INIT_PRIORITY_LIBRARY )