pcntl_unshare() allows a process to disassociate parts of its execution context that are
currently being shared with other processes.
The main use of pcntl_unshare() is to allow a process to control
its shared execution context without creating a new process.
参数
flags
The flags parameter is a bitmask that specifies which parts of the execution context should be unshared.
This parameter is specified by ORing together zero or more of the CLONE_* constants:
