How to cleanly interrupt a thread blocking on a recv call?

Question

I have a multithreaded server written in C, with each client thread looking something like this:

ssize_t n;
struct request request;

// Main loop: receive re         


        

Answer 1

So you have at least these possibilities:

(1) pthread_kill will blow the thread out of recv with errno == EINTR and you can clean up and exit the thread on your own. Some people think this is nasty. Depends, really.

(2) Make your client socket(s) non-blocking and use select to wait on input for a specific period of time before checking if a switch used between the threads has been set to indicated they should shut down.

(3) In combo with (2) have each thread share a pipe with the master thread. Add it to the select. If it becomes readable and contains a shutdonw request, the thread shuts itself down.

(4) Look into the pthread_cancel mechanism if none of the above (or variations thereof) do not meet your needs.