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/*

 * tclUnixEvent.c --

 *

 *      This file implements Unix specific event related routines.

 *

 * Copyright (c) 1997 by Sun Microsystems, Inc.

 *

 * See the file "license.terms" for information on usage and redistribution

 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.

 *

 * RCS: @(#) $Id: tclUnixEvent.c,v 1.1.1.1 2002-01-16 10:25:37 markom Exp $

 */

#include "tclInt.h"

#include "tclPort.h"

/*

 *----------------------------------------------------------------------

 *

 * Tcl_Sleep --

 *

 *      Delay execution for the specified number of milliseconds.

 *

 * Results:

 *      None.

 *

 * Side effects:

 *      Time passes.

 *

 *----------------------------------------------------------------------

 */

void

Tcl_Sleep(ms)

    int ms;                     /* Number of milliseconds to sleep. */

{

    static struct timeval delay;

    Tcl_Time before, after;

    /*

     * The only trick here is that select appears to return early

     * under some conditions, so we have to check to make sure that

     * the right amount of time really has elapsed.  If it's too

     * early, go back to sleep again.

     */

    TclpGetTime(&before);

    after = before;

    after.sec += ms/1000;

    after.usec += (ms%1000)*1000;

    if (after.usec > 1000000) {

        after.usec -= 1000000;

        after.sec += 1;

    }

    while (1) {

        delay.tv_sec = after.sec - before.sec;

        delay.tv_usec = after.usec - before.usec;

        if (delay.tv_usec < 0) {

            delay.tv_usec += 1000000;

            delay.tv_sec -= 1;

        }

        /*

         * Special note:  must convert delay.tv_sec to int before comparing

         * to zero, since delay.tv_usec is unsigned on some platforms.

         */

        if ((((int) delay.tv_sec) < 0)

                || ((delay.tv_usec == 0) && (delay.tv_sec == 0))) {

            break;

        }

        (void) select(0, (SELECT_MASK *) 0, (SELECT_MASK *) 0,

                (SELECT_MASK *) 0, &delay);

        TclpGetTime(&before);

    }

}