linux 多线程与信号pthread_kill

from man page

NAME
       pthread_kill - send a signal to a thread

SYNOPSIS
       #include <signal.h>

       int pthread_kill(pthread_t thread, int sig);

       Compile and link with -pthread.

DESCRIPTION

       The pthread_kill() function sends the signal sig to thread, a thread in the same process as the caller.  The signal is asynchronously directed to thread.也就是同一进程内部线程之间使用。

       If sig is 0, then no signal is sent, but error checking is still performed; this can be used to check for the existence of a thread ID.

RETURN VALUE
       On success, pthread_kill() returns 0; on error, it returns an error number, and no signal is sent.

ERRORS
       EINVAL An invalid signal was specified.

       ESRCH  No thread with the ID thread could be found.

CONFORMING TO
       POSIX.1-2001.

NOTES
       Signal dispositions are process-wide: if a signal handler is installed, the handler will be invoked in the thread thread（pthread_kill的参数）, but if the disposition of the signal
       is "stop", "continue", or "terminate", this action will affect the whole process.