#include <pthread.h>
#include <stdio.h>

void *hola(void *)
{
    printf("[%lu]: hola\n", pthread_self());
    return NULL; // pthread_exit(NULL);
}

int main()
{
    pthread_t id = 0;
    hola(NULL);
    pthread_create(&id, NULL, hola, NULL);
    pthread_join(id, NULL);
}