Hello Guys

I've a small program looking for a specific window.
If finds the window, the login button will be clicked.
So far everything looks fine. But my question is,
should I validate the handle, if the window was
found or not and jump somewhere else, if not?
By now it would search, if not found it will try to
click the button, but the handle is null. Seems like
fasm handles this quite good. but what would you say?

thank you!

What type of handles are you talking about? If you are using FindWindow to look for a window, then it will return NULL if the window cannot be found. Further feeding in NULL as the parent window handle to an API such as FindWindowEx will likely result in another NULL return. Sending message to a NULL window would also likely fail. But the point is you are relying on strictly defined behaviour of these APIs in the error/invalid-parameter path, which I would avoid if I could. So personally, I would check the return value of each step of your program, and "jump somewhere else" if anything fails.

Thank you very much, comrade!