A simple loop with the 'doevents' command an checking
the the system time uses 100% of CPU-Time.
Now I am using the timer control-element to call a subroutine
at 1 second interval for example and then counting the elapsed
time.
Does anyone know a better/easyer way to do this ?

A few months ago I was wondering how VB manages to 'halt' the flow of
execution when you display a modal form.

That led me to do a little digging around - and I found something that
I've never seen mentioned on the NGs

the WaitMessage API

What it does is sit waiting for a Windows Message - unlike Sleep that
literally halts the thread - and unlike a DoEvents loop that 'eats'
CPU time.

While Something = False
           WaitMessage
           DoEvents
           ' Me.Print ".";
           ' DoEvents
Wend

Knock out the comment characters and you should see what it does.

Using this I have managed to port a DOS Touchscreen Application to
Windows - it uses something like 50 screens - but only one Form as I
paint all the screens myself.

The nice thing about it is that the code does _not_ have to be a
tangle of Events - all I do is paint a screen and wait until the user
'clicks' on a 'vector' - at which point it comes back with the 'key'
of the thing they clicked - the whole thing runs off the 'strand of
execution' from Sub Main

One could use this method to port DOS Applications that rely on InKey

My hunch is that this could also be used to 'supervise' normal
controls.

In your case you just release the WaitMessage loop using a flag set by
the timer and your code continues where you left off.

On Wed, 27 Mar 2002 09:30:34 +0100, "Goebel, Matthias"

Personally, I would stick with the Sleep API for such purposes. If you use a
10 millisecond Sleep period in a loop and your code checks the elapsed time
at each iteration of the loop (and issues a DoEvents) then your app will
remain responsive and your "paused" code will still wait for whatever period
you specify. The time taken for your code to check the elapsed time and to
Do the Events would invariably be very small (almost insignificant when
compared to 10 milliseconds) and so your "paused" code block is effectively
using almost no processor time at all during the total "Sleep". I think the
original poster was using a DoEvents in a loop without using a Sleep in the
same loop, and that is why his app was using a significant amount of
processor time during the "wait".

WaitMessage is, however, extremely useful for some purposes, as you have
suggested.

Hi Mike,

Or should I say 'Maureen' as you have your frock on today.

The Waitmessage waits for a message - but if the OP sets up a Timer
then he should get a message.

Realistically it depends what he wants to do - if he is happy 'dying'
for say 60 secs then Sleep is the answer
- if on the other hand he wants to keep a semblance of 'life'
- well then it is lots of 'little Sleeps' rather than one 'Big Sleep'
- or using Waitmessage.

Regardless - I am so chuffed at having found a way of making Windows
work 'sanely' that I'm keen to see what others come up with.

Or maybe a 'DefInt A-Z' will do

On Wed, 27 Mar 2002 13:27:42 -0000, "Maureen"