send message to exe from dll

Hi, I have a dll that I am using to listen for keyboard events system-wide, however, I want to send a message back to the exe that called the dll in certain cases. i don't really know what i'm doing, so i have no idea what kind of function i would use. i'm looking for something like "PostMessage(WM_THISKEYWASPRESSED)" that would also take some kind of paramter to know to send that message back to the calling exe. is this possible? if so, what function do i need to use? i would appreciate a short code snippet if possible. thank you!

Tom

first, i think this program should based on threaded model. So, ::PostMessage(hwnd,WM_, PARA,PARA), or PostThreadMessage(..), if another thread can receive message, can be used here.

the dll only need to know where the keyboard message should be post. The destination can be a window or a thread.

Hello!
I am sure you installed a keyboardhook in your dll an now you want to send the keyboardevents to your window. It´s an better idea to send!!! a WM_COPYDATA event to your window.
cu