exemplu.c

#include <stdio.h>
#include <pthread.h>
#define NUM_THREADS 5

// mutex global
pthread_mutex_t mutex;
int global_counter = 0;

void *thread_routine( )
{
  pthread_mutex_lock(&mutex);
  pthread_mutex_lock(&mutex);

  printf("am ajuns in zona protejata de mutex\n");

  pthread_mutex_unlock(&mutex);
  pthread_mutex_unlock(&mutex);
}

int main(void) {
  int i;
  pthread_t tids[NUM_THREADS];

  // definim atribute, le initializam si marcam tipul ca fiind recursiv.
  pthread_mutexattr_t attr;
  pthread_mutexattr_init(&attr);
  pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
  // definim un mutex recursiv, il initializam cu atributele definite anterior

  pthread_mutex_init(&mutex, &attr);

  pthread_mutexattr_destroy(&attr);

  // firele de executie vor executa codul functiei 'thread_routine'
  // in locul unui pointer la date utile, se trimite in ultimul argument
  // un intreg - identificatorul firului de executie
  for (i = 0; i < NUM_THREADS; i++)
    pthread_create(&tids[i], NULL, thread_routine, (void *) i);

  // asteptam ca toate firele de executie sa se termine
  for (i = 0; i < NUM_THREADS; i++)
    pthread_join(tids[i], NULL);

  // eliberam resursele mutexului
  // eliberare mutex
  pthread_mutex_destroy(&mutex);
  return 0;
}