I'm running a simple web server and seem to be having a problem canceling sessions.


When a new request is received I start a thread to handle that session's requests. Since I want to keep the pipe open for a long time - 10 minutes or maybe 2 hours - I also have a session manager that checks for inactivity. When the time is up I want to cancel the session thread.


The problem is I don't think the thread is getting canceled and I'm leaking memory with zombie sessions. I've set the threads for asynchronous cancellation but I'm getting a return code of 3 and I should get all zeroes per the manual.


Server code:
pthread_create( &NewSessionThread, NULL, &HTTP_Server_Session, (void *) (NewSessionListItem));






Session code:
pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, oldstate);
pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, oldtype);






Session manager code:
CancelResult = pthread_cancel(SessionPointer->SessionThreadID);


fprintf(CrashLog, "HTTP pthread cancellation result (0, success - other not): %d\n", CancelResult);
if (CancelResult == 3)
fprintf(CrashLog, "HTTP pthread cancellation error: %s\n", strerror(errno));








Logfile sample result:
HTTP pthread cancellation result (0, success - other not): 3
HTTP pthread cancellation error: Success




I guess I have three questions:
Why isn't the cancellation working?
Why is the error string “Success” when the result is not 0?
How should I try to fix it?


Thanks!