PostThreadMessage usage across threads created in two c++ files

I have a thread created in the main function开发者_如何学C and PostThreadMessage from ther is invoked with the corresponding thread ID. If one more thread is created in a seperate file how can we invoke PostThreadMessage as we dont know the thread ID which is a parameter for invoking

You have to either:

1. Store/pass the thread ID (or thread handle) from whatever created the thread to whatever needs to know about the thread; or

2. Have some way to find the thread via an object it creates. (e.g. If it creates a window with a unique class, you could find that window and then ask the OS which thread owns the window.)

Other than that, there is no magical way to "find a particular thread with no known attributes that was created by another thread that didn't tell anyone about", unless you want to enumerate all threads within your process (but you would have no way to know thread was the right one, unless you did something like #1 or #2 above, and if you do either of them then you don't need to enumerate in the first place).

Note that there will almost always be more threads in your process than the ones you explicitly create, so you cannot just look for "any thread except the two I already know about," because you might pick up a system worker-thread or similar that you should not mess with.