import ctypes

def mouse_released() -> bool:
    mouse_state = ctypes.windll.user32.GetAsyncKeyState(0x01)
    if mouse_state:
        while ctypes.windll.user32.GetAsyncKeyState(0x01):
            continue  # is pressing
        else:
            print('released')
            return mouse_state != 0 # released
    return False

while True:
    mouse_released()

This program tells if the left mouse button was released.

Problem: in general it works correctly. But sometimes at the very beginning it prints “released”, even though nothing was pressed even a few seconds before.

I tried to change the GetAsyncKeyState with GetKeyState. It seemed to solve the mentioned problem, but this way, the function indicates the button being pressed only every second time, which is a complete mistery to me.