c++ event loop in sub application in a dll

Question

Good day,

I have the following issue: I have one exe application that writes text files to the disk, and that exe source is unavailable. Customer has asked that, when users press numpad 5, a new window pops up, and does some operations with some files.

Problem is, numpad 5 + new application popup MUST only work when the application is running and has focus (they use numpad 5 for other operations).

I thought about this

1. create a dll with a form and buttons that do the required actions
2. inject the dll in the process

But I'm struggling to understand if there is a way to create a "keypress loop" in the dll.

Please note that I'm a beginner in c++ and forms, but I just need a feasibility check and a direction.

Is it possible to create a window application that waits for a keypress in an injected dll? Is it there any simple example of this? Using google like a madman I was unable to find references to this so I think I have a problem with the proper terms.

My main issue is that the dllmain is obviously a one shot routine, and I don't understand how to create an "event loop".

Thanks for any information provided.

Answer 1

If you have successfully managed to inject your DLL in the traget process, use the _beginthread API in DllMain to start a new thread, and in that thread you can create a Dialog Box and have a message loop in the usal way.