I can not find clone() in the sched.h header file.
Where is it on Mac OS X?
man 2 clone says:
The clone() and sys_clone calls are Linux-specific and should not be used in programs intended to be portable.
clone() is a Linux-specific call and doesn't exist in OSX.
来源：https://stackoverflow.com/questions/8320174/where-is-clone-method-in-sched-h-on-mac-os-x