Button click event after call DLL

In form, I made a "stop" button and call dll procedure that loop exists in it.
After call dll, must detect button click event.
I other words, in c-coded dll, detect button click event generated in VB.
How can I do it?
Someone let me know that I must use the function that pending windows event in c-coded DLL.
But I cannot implement it.
Could anyone who know it let me know the way.
Thanks.


I'm a senior programmer.
Working at CamSight, Dental imaging solutions industry.