stk/Tcl/tclUnixEvent.c

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1998-04-10 06:59:06 -04:00
/*
* 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.
*
* SCCS: @(#) tclUnixEvent.c 1.1 97/03/04 14:19:34
*/
#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);
}
}