exit_group - 退出所有執行緒在一個進程
#includevoid exit_group(int status);
This system call is equivalent to exit(2) except that it terminates not only the present thread, but all threads in the current thread group.
這個系統呼叫無返回。
This call is present since Linux 2.5.35.
這個呼叫是Linux特有的。