Thread-Specific Data: Example - Main.

#include <pthread.h>
#include <stdlib.h>

pthread_key_t    key1, key2;
void destruct(void *value), start_func(int thread_num);

main()
{
    int        ret_val;
    pthread_t    tid1;
    ret_val = pthread_key_create(&key1, (void *) NULL);
    ret_val = pthread_key_create(&key2, destruct);
    ret_val = pthread_create(&tid1, (pthread_attr_t *)NULL,
            (void *(*)(void *))start_func,(void *) 1);
    start_func(0);
    ret_val = pthread_join(tid1, (void **)NULL);
    ret_val = pthread_key_delete(key1);
    ret_val = pthread_key_delete(key2);
}