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  1. #include <stdio.h>
  2. #include <pthread.h>
  3.  
  4. #define THREADS 5
  5.  
  6. int shared = 0;
  7. pthread_mutex_t lock;
  8.  
  9. void* increment(void* arg) {
  10.     for(int i = 0; i < 100000; i++) {
  11.         pthread_mutex_lock(&lock);
  12.         shared++;
  13.         pthread_mutex_unlock(&lock);
  14.     }
  15.     return NULL;
  16. }
  17.  
  18. int main() {
  19.     pthread_t threads[THREADS];
  20.  
  21.     pthread_mutex_init(&lock, NULL);
  22.  
  23.     for(int i = 0; i < THREADS; i++) {
  24.         pthread_create(&threads[i], NULL, increment, NULL);
  25.     }
  26.  
  27.     for(int i = 0; i < THREADS; i++) {
  28.         pthread_join(threads[i], NULL);
  29.     }
  30.  
  31.     pthread_mutex_destroy(&lock);
  32.  
  33.     printf("Final value of shared variable = %d\n", shared);
  34.  
  35.     return 0;
  36. }
Success #stdin #stdout 0.02s 5288KB
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stdout
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Final value of shared variable = 500000
https://ideone.com/Ufu8cw
language:
C (gcc 8.3)
created:
1 day ago
visibility:
public

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