Pass A Function Pointer From A C Dll To A C Dll

I am trying to use the Windows function: https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setwindowshookexa to register a global hook. I have created a hook pr

Solution 1:

I got the callback working and the hook registered with the following code:

# Set callback from windows hook procedure to our python code
dll_name = "FSHooks.dll"
dll_abspath = os.path.abspath(os.path.join(os.path.dirname(__file__), '..', 'Win32',
                                           'Debug', dll_name))
dll_handle = cdll.LoadLibrary(dll_abspath)
self.callback_type = CFUNCTYPE(None, c_int, c_int, c_int, c_bool)
self.callback = self.callback_type(self.callback_from_c)

dll_handle.Init()
dll_handle.SetCallback(self.callback)
# TODO - Release the hooks when window closes# Register the hook
dll_handle.HookProc.argtypes = (c_int, wintypes.WPARAM, wintypes.LPARAM)
hook_proc_pointer = dll_handle.HookProc
self.hook_id = windll.user32.SetWindowsHookExA(win32con.WH_MOUSE_LL, hook_proc_pointer,
                                               win32api.GetModuleHandle(None), 0)

It appears you can just take the attribute that is the name of the function in the dll and it accepts it as a pointer argument. I had to set the argument types and it worked.