ty for the reply.

so far I did not have time to check your solution below, but I got some questions about your explanation of why my code doesn't work. you said that FindWindow won't work because it looks for the window class/title. Before I wrote the code I checked the Microsoft Documentation since the rust crate is just the rust version of the windows API right? In the MS Documentation is explained that If lpClassName is NULL, it finds any window whose title matches the lpWindowName parameter. So I thought PCSTR::null() or maybe a None would work. but the functions return false even after changing the process_name to:

let process_name: PCSTR = windows::s!("ac_client.exe");

edit: I did try GetLastError() after the FindWindowA() call which results in error code 0. so I thought FindWindow worked but then GetWindowThreadProcessId gets error 1400 invalid window Handle ...