Thread: pthread create and join problems

i have a daemon process that creates and joins multiple threads.

every so often the pthread error check will fail and the program terminate.

under what conditions would the pthread_create function fail?

i'm really looking for some practical reasons. i believe that the code is correct.

i'm also having problems with pthread_join hanging randomly.

any ideas?

TIA, rotis23

Code:

*************************************************

        pthread_exit(NULL);     //end of thread_function

*************************************************

        int res;
        int lots_of_threads;
        int num_sites;
        pthread_t a_thread[5];
        void *thread_result;

        //initialise mutex - used to synchronise linked list between threads
        res = pthread_mutex_init(&queue_mutex, NULL);
        if (res != 0){printf("mutex creation failure.\n");

        //add multiple threads
        for(lots_of_threads = 0; lots_of_threads < 5; lots_of_threads++)
        {
                //threads are created and started
                res = pthread_create(&(a_thread[lots_of_threads]), NULL,
thread_function, (void *)lots_of_threads);
                if (res != 0){printf("create failure.\n");
        }

        //wait for threads to finish and clean up
        printf("Waiting for threads to finish...\n");

        for(lots_of_threads = 5 - 1; lots_of_threads >= 0;
lots_of_threads--)
        {
                res = pthread_join(a_thread[lots_of_threads], NULL);
                if (res == 0)
                {
                        printf("Picked up a thread\n");
                }
                else{printf("join error.\n");
        }

where can i find the error list?