Re: pthreads bug - memory leak

diego el gordito writes:
> As requested by Chad Loder <cloder@openbsd.org)

I enjoyed! Note for the future, attachments are stripped, send the code in line. But no need to resend this time, as I can explain the problem.

Your code contains this:

        pthread_mutex_t condition_mutex = PTHREAD_MUTEX_INITIALIZER;
        pthread_cond_t  condition_cond  = PTHREAD_COND_INITIALIZER;

The problem here is that both pthread_mutex_t and pthread_cond_t are pointers and the initializer is nothing but NULL. They are not really static variables. pthreads is semi-smart in that it will allocate memory and initialize the values for you, in effect calling pthread_cond_init and pthread_mutex_init behind your back.

However, the thread code can't tell when the variables go out of scope or are no longer being used, so it can not call pthread_mutex_destroy or pthread_cond_destroy for you. You have to do it yourself. Adding

	pthread_cond_destroy(&condition_cond);
	pthread_mutex_destroy(&condition_mutex);

to the end of your tsleep subroute is necessary for proper operation. Doing that will stop unlimited growth. On an i386 running -current memory use stabilizes at 40K.

// marc Received on Fri Jan 24 17:02:52 2003