ProcessSystemEvents & callback functions

[MrIncognito]

Hello.

I have a question about the ProcessSystemEvents() and callback functions. If I have the following "strange" callback function with the follwoing code inside:

int func(...) {

  while(true) {

   ProcessSystemEvents();

  }

}

Could this code create a crash in the underlying run-time lib (cvirte.dll etc), with to many calls to ProcessSystemEvents?

And will this code stop any other callback function from execution, since we are in an infinite while loop?

Best regards,
Christian G.

[RobertoBozzolo]

The answer is "no" to both questions: processSystemEvents has been designed exactly to permit handling user and system events that normally would not be processed in situations like your loop.

[MrIncognito]

Hello! Thank you for the quick answer, it is very much appreciated.

If the callback function above is set at an intervall of say 100 times per second, how will the system react to that? Since the callback function is never terminated, will the system still keep on generating call to this never ending callback? Could this make the system crash?

Best regards,

Christian G.

[RobertoBozzolo]

A fuction like that should be called only once, if this is what you intend. While sitting in the loop, ProcessSystemEvents permits the system to react to events like the user pressing a button or something like this. You must explicitly avoid dangerous events like calling the function again and again, as well as all user actions that can cause problems (like modifying critical parameters while the function is running, improperly exiting the program and so on). To obtain this you may either disable unwanted buttons on the GUI or set a global flag 'system running' tested on all callbacks and functions to protect the system from unwanted operations.