[StackOverflow/python] How to avoid X11 race condition when multithreading with PyAutoGUI?

### ROOT CAUSE The issue arises because PyAutoGUI's X11 backend (used on Linux) does not handle concurrent input operations properly. Multiple threads can send mouse/keyboard events simultaneously, causing unpredictable behavior due to the X11 server processing events in an arbitrary order, leading to race conditions. ### CODE FIX Use a `threading.Lock` to serialize access to PyAutoGUI's input functions. Here's an example implementation: ```python import threading import pyautogui # Create a global lock input_lock = threading.Lock() def safe_click(x=None, y=None, button='left', duration=None): """Thread-safe wrapper for pyautogui.click""" with input_lock: pyautogui.click(x=x, y=y, button=button, duration=duration) def safe_move(x, y): """Thread-safe wrapper for pyautogui.moveTo""" with input_lock: pyautogui.moveTo(x, y) # Replace direct calls with safe wrappers in your code: # safe_click(x=100, y=200) # safe_move(300, 400) ``` **Explanation:** 1. The `input_lock` ensures only one thread can execute input-related PyAutoGUI functions at a time. 2. All mouse/keyboard operations must use the `safe_*` wrappers instead of direct `pyautogui` calls. 3. This prevents concurrent X11 event sending, eliminating the race condition. **Note:** For complex multithreaded applications, consider creating a dedicated input controller thread to handle all PyAutoGUI operations, ensuring no direct thread access to input functions.