pthread_kill

参考：

要点：

• 待取消线程需要注册信号处理函数，否则把主进程干掉了

• 外部线程发起kill
  (触发待kill 线程响应对应的信号)

• 处理pthread_kill 的返回值

• 参考：
  https://blog.csdn.net/vah101/article/details/40393287

pthread_cancel

要点：
* 待取消的线程内部需要设置可取消属性；

• 外部发取消命令

考虑如何释放待取消线程占用、申请的资源

参考：
http://blog.sina.com.cn/s/blog_66fb0c830100y9hb.html

对应正在执行的线程如何cancel掉

使用: pthread_testcancel

NAME
       pthread_testcancel - request delivery of any pending cancellation request

SYNOPSIS
       #include <pthread.h>

       void pthread_testcancel(void);

       Compile and link with -pthread.

DESCRIPTION
       Calling pthread_testcancel() creates a cancellation point within the calling thread,
       so that a thread that is otherwise executing  code  that  contains  no  cancellation
       points will respond to a cancellation request.

       If  cancelability  is disabled (using pthread_setcancelstate(3)), or no cancellation
       request is pending, then a call to pthread_cancel() has no effect.

RETURN VALUE
 This function does not return a value.  If the calling thread is canceled as a  con-
       sequence of a call to this function, then the function does not return.

参考https://www.cnblogs.com/tianzeng/p/9195091.html