“+[SomeClass initialize] may have been in progress in another thread when fork() was called”

python multiprocessing程序运行时，报错：

objc[2483]: +[__NSPlaceholderDate initialize] may have been in progress in another thread when fork() was called.objc[2483]: +[__NSPlaceholderDate initialize] may have been in progress in another thread when fork() was called. We cannot safely call it or ignore it in the fork() child process. Crashing instead. Set a breakpoint on objc_initializeAfterForkError to debug.

---

解决方法：添加环境变量：

OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES

---

附图：

---

参考：

• http://sealiesoftware.com/blog/archive/2017/6/5/Objective-C_and_fork_in_macOS_1013.html