Terminating a blocked pthreads thread

Question

I Have a thread that reads data from a file descriptor, using select() to block until the data is available. When the program needs to terminate, I need to close the thread, however it's blocked on select.

My question, is it a good practice to notify the thread about my intentions to terminate by closing the file-descriptor ?

is there a better method to notify the thread ? I know there's always an option to use signal, however I've read in some places that signals the pthreads doesn't work together that well.

Answer 1

Well you can use a pipe, and add that to your read-set. Send a single byte on the pipe when the thread should terminate.

Or have a timeout on the select call, and when it timeouts check for termination flag.

Answer 2

In addtion to the gentle ways proposed by Joachim , there also are some rough appoaches to "interrupt" the blocking select() :

• use pthread_kill() to send a signal to the blocking thread and test for (EINTR == errno) after the select() in question
• call pthread_cancel() on the thread-id. select() belongs to the set of default cancellation points.

Both methods should be considert as last ressort solutions.