Why isn't something simple like the following:
// display some text...
SysTaskDelay (SysTicksPerSecond ()/2);
// erase the text...
sufficient to hold up processing for a brief period (in this case 1/2
second) in order to display some text and then erase it?
Mitch
> -----Original Message-----
> From: Danny Epstein [SMTP:[EMAIL PROTECTED]]
> Sent: Monday, September 27, 1999 9:30 PM
> To: [EMAIL PROTECTED]
> Subject: Re: EvtSetNullEventTick macro
>
> At 8:27 PM -0700 9/18/99, Sudipta Ghose wrote:
>
> In the datebook source code, I found a macro named
> EvtSetNullEventTick. The macro sets an OS global called NeedNullTickCount.
> If I use this macro in my code pose gives a warning (as it should). My
> question is how safe is to use the macro? How does this global affects the
> generation of nilEvents?� Is there any alternatives? What I need to do, is
> to display some text for few seconds, and then erase the text.
>
>
> Scott Johnson answered your question a long time ago, but he didn't give
> any details on how do what EvtSetNullEventTick does yourself. I used
> EvtSetNullEventTick during development of BeamBooks, but I switched to my
> own ProduceNilEventAt routine before release.
>
> You need a global variable, say:
>
> // When to produce a nil event, or zero if never.
> static ULong NilEventTicks = 0;
>
> Then you need a routine like this:
>
> void ProduceNilEventAt(ULong ticks)
> {
> ��� if (NilEventTicks == 0 || NilEventTicks > ticks)
> ������� ������� NilEventTicks = ticks;
> }
>
> Then you need to modify your app event loop like this:
>
> static void AppEventLoop(void)
> {
> ULong now;
> ������� SDWord timeout;
> ������� ...
> �������
> ������� do
> ����� {
> ������ ������� if (NilEventTicks == 0)
> �������� ������� ������� timeout = evtWaitForever;
> ������ ������� else
> ��� ������� {
> ������ ������� ������� now = TimGetTicks();
> ��� ������� ������� timeout = NilEventTicks > now ? NilEventTicks - now :
> 0;
> ������� ������� }
> ������� ������� EvtGetEvent(&event, timeout);
> �� ������� if (event.eType == nilEvent)
> ��� ������� ������� NilEventTicks = 0;
> ����� ������� if (! SysHandleEvent(&event))
> ������� ������� ������� ...
> ���� }
> ������ while (event.eType != appStopEvent);
> }
>
> When I get a nilEvent, I don't assume that my wait is over. The nilEvent
> could have been generated by Palm OS. I use a separate tick clock to
> check. Here's an example of how you could use ProduceNilEventAt to hide
> some text after a few seconds:
>
> #define kHideTextDelay� ������� ������� ������� 300ul
>
>
> static ULong HideTextTicks;
>
> static void LoadSomeForm(FormPtr formP)
> {
> ������� HideTextTicks = TimGetTicks() + kHideTextDelay;
> ������� ProduceNilEventAt(HideTextTicks);
> }
>
>
> Boolean SomeFormHandleEvent(EventPtr eventP)
> {
> ������� ...
> ������� if (HideTextTicks != 0 && TimGetTicks() > HideTextTicks)
> ������� ������� ... hide text here ...
> ������� switch (eventP->eType)
> ������� {
> ������� ������� ...
> ������� ������� case nilEvent:
> ������� ������� ������� if (HideTextTicks != 0)
> ������� ������� ������� ������� ProduceNilEventAt(HideTextTicks);
> ������� ������� ������� break;
> ������� }
> ������� return handled;
> }
>
> Hope this isn't too late to be useful...
> -
> Danny Epstein, Applied Thought Corporation
> Check out our latest app at http://www.appliedthought.com/beambooks
