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  1. #include <stdio.h>
  2. #include <pthread.h>
  3. #include <semaphore.h>
  4. #include <unistd.h>
  5.  
  6. sem_t mutex;
  7. int shared = 0;
  8.  
  9. void* work(void* arg)
  10. {
  11.     sem_wait(&mutex);
  12.     shared++;
  13.     printf("Thread %d entered critical section. Shared = %d\n", *(int*)arg, shared);
  14.     sleep(1);
  15.     printf("Thread %d leaving critical section.\n", *(int*)arg);
  16.     sem_post(&mutex);
  17.     return NULL;
  18. }
  19.  
  20. int main()
  21. {
  22.     pthread_t t1, t2;
  23.     int id1 = 1, id2 = 2;
  24.  
  25.     sem_init(&mutex, 0, 1);
  26.  
  27.     pthread_create(&t1, NULL, work, &id1);
  28.     pthread_create(&t2, NULL, work, &id2);
  29.  
  30.     pthread_join(t1, NULL);
  31.     pthread_join(t2, NULL);
  32.  
  33.     sem_destroy(&mutex);
  34.     return 0;
  35. }
Success #stdin #stdout 0.01s 5296KB
comments (?)
stdin
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Standard input is empty
stdout
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Thread 2 entered critical section. Shared = 1
Thread 2 leaving critical section.
Thread 1 entered critical section. Shared = 2
Thread 1 leaving critical section.
https://ideone.com/W4eT3H
language:
C (gcc 8.3)
created:
1 day ago
visibility:
public

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