Mac上python多线程错误：...+[__NSPlaceholderDate initialize]...

错误提示并且报pycharm异常退出

objc[27880]: +[__NSPlaceholderDate initialize] may have been in progress in another thread when fork() was called.
objc[27880]: +[__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.

刚开始以为是代码的问题，后来才发现其实是macOS的High Sierra以上的操作系统对多线程的限制

解决办法

1、在终端运行代码之前  export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES 临时解决

2、  sudo echo "export OBJC_DISABLE_INITIALIZE_FORK_SAFETY=YES" >> ~/.bash_profile && source ~/.bash_profile 长久解决

但是这个加上去之后我写的flask接口会报错，导入猴子包就ok

if __name__ == "__main__":
    from gevent import monkey
    monkey.patch_all()
    app.run(debug=True, host='0.0.0.0', port=5000)

3、　打开pycharm

 

完美解决！！！！