Multithreading - Callback functions from within a Callback function

[dabir]

I setup up a new thread which calls the callback function X. In function X, I have, from the Programmer's Toolbox library the function 'OutputList()' which is set to call another callback function Y. The problem is that the callback function Y never gets called. Similarly, I found that ProcessTcpEvents() in another thread does not process the tcp event function which is in the main thread. Is there a way round this problem?

[bilalD]

Hello dabir

Each thread is responsible for processing its own messages. So if you have a tcp event function in your main thread, calling ProcessTCPEvents in another thread will not process the messages in the main thread. You will need to have some sort of process loop happening in your main thread for its messages.
For example, if you have a UI application that is your main thread, RunUserInterface or a while loop of ProcessSystemEvents will be responsible for processing all the UI messages and any other system events that the UI thread receives. If you launch another UI from a seperate thread, that thread will need its own ProcessSystemEvents to handle the UI messages, the main UI thread will not process messages for all the UI in all threads.
So per
haps in the case of your application, you need a message loop in your new thread to make sure you process all the callbacks. This is not something CVI specific, but is standard Windows behavior.

Hope this helps

Bilal Durrani
NI