unhookwindowshookex

I have a DLL I inject into other processes using SetWindowsHookEx . Inside the DLL I increment the module's reference counter by calling GetModuleHandleEx so I can control when the module is unloaded. At this point the module reference count "should be" 2 from both of those API calls. When the calling process shuts down, it calls UnhookWindowsHookEx , decrementing the reference count to 1. The DLL has a thread that waits on a few things, one of them being the handle of the process that called SetWindowsHookEx . When the process goes away the DLL does some cleanup, terminates all threads,

How do you properly unload a DLL from all processes when the system-wide hook that loaded them gets unloaded? From MSDN : You can release a global hook procedure by using UnhookWindowsHookEx, but this function does not free the DLL containing the hook procedure . This is because global hook procedures are called in the process context of every application in the desktop, causing an implicit call to the LoadLibrary function for all of those processes. Because a call to the FreeLibrary function cannot be made for another process, there is then no way to free the DLL. The system eventually frees