To exit from the while(1) loop

Question

Hi all ,
I have a simple question that if in a callback function of a command button, i use a While(bLoop)
loop , where bLoop is a boolean variable initially set to TRUE, then how can i break or exit from this while Loop by using a control on the front panel  , which exits the while loop by setting     bLoop = FALSE .
I have tried it but it is not exiting  
Solved!
Go to Solution.

Answer 1

The problem here is that CVI normally only executes one callback at a time. While you are in one control callback, no GUI processing and subsequent calls to other callbacks normally occurs.
You can try the following approach - but it is not really the best method:
    while (b_loop) {              // Inside a callback
        ...                       // Perform your tight program loop
        ProcessSystemEvents ();   // Force CVI to see if any GUI controls need servicing
If you have a different control callback to clear the global b_loop, this quick-and-dirty approach might work for you.
You should only use this technique for very simple programs - it can rapidly spiral out of control and end up in a mess if you're not careful. NI recommends that you do not use ProcessSystemEvents() inside a control callback.
JR