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  1. #include <pthread.h>
  2. #include <stdio.h>
  3. #include <stdlib.h>
  4. #include </usr/include/semaphore.h>
  5.  
  6. // for sleep
  7. #include <unistd.h>
  8.  
  9. #define BUFF_SIZE   5           /* total number of slots */
  10. #define NP          3           /* total number of producers */
  11. #define NC          3           /* total number of consumers */
  12. #define NITERS      4           /* number of items produced/consumed */
  13.  
  14. typedef struct
  15. {
  16.     int buf[BUFF_SIZE];   /* shared var */
  17.     int in;               /* buf[in%BUFF_SIZE] is the first empty slot */
  18.     int out;              /* buf[out%BUFF_SIZE] is the first full slot */
  19.     sem_t full;           /* keep track of the number of full spots */
  20.     sem_t empty;          /* keep track of the number of empty spots */
  21.  
  22.     // use correct type here
  23.     pthread_mutex_t mutex;          /* enforce mutual exclusion to shared data */
  24. } sbuf_t;
  25.  
  26. sbuf_t shared;
  27.  
  28.  
  29. void *Producer(void *arg)
  30. {
  31.     int i, item, index;
  32.  
  33.     index = (int)arg;
  34.  
  35.  
  36.     for (i=0; i < NITERS; i++)
  37.     {
  38.  
  39.         /* Produce item */
  40.         item = i;
  41.  
  42.         /* Prepare to write item to buf */
  43.  
  44.         /* If there are no empty slots, wait */
  45.         sem_wait(&shared.empty);
  46.         /* If another thread uses the buffer, wait */
  47.         pthread_mutex_lock(&shared.mutex);
  48.         shared.buf[shared.in] = item;
  49.         shared.in = (shared.in+1)%BUFF_SIZE;
  50.         printf("[P%d] Producing %d ...\n", index, item);
  51.         fflush(stdout);
  52.         /* Release the buffer */
  53.         pthread_mutex_unlock(&shared.mutex);
  54.         /* Increment the number of full slots */
  55.         sem_post(&shared.full);
  56.  
  57.         /* Interleave  producer and consumer execution */
  58.         if (i % 2 == 1) sleep(1);
  59.     }
  60.     return NULL;
  61. }
  62.  
  63. void *Consumer(void *arg)
  64. {
  65.     int i, item, index;
  66.  
  67.     index = (int)arg;
  68.     for (i=NITERS; i > 0; i--) {
  69.         sem_wait(&shared.full);
  70.         pthread_mutex_lock(&shared.mutex);
  71.         item=i;
  72.         item=shared.buf[shared.out];
  73.         shared.out = (shared.out+1)%BUFF_SIZE;
  74.         printf("[C%d] Consuming  %d ...\n", index, item);
  75.         fflush(stdout);
  76.         /* Release the buffer */
  77.         pthread_mutex_unlock(&shared.mutex);
  78.         /* Increment the number of full slots */
  79.         sem_post(&shared.empty);
  80.  
  81.         /* Interleave  producer and consumer execution */
  82.         if (i % 2 == 1) sleep(1);
  83.     }
  84.     return NULL;
  85. }
  86.  
  87. int main()
  88. {
  89.     pthread_t idP, idC;
  90.     int index;
  91.  
  92.     sem_init(&shared.full, 0, 0);
  93.     sem_init(&shared.empty, 0, BUFF_SIZE);
  94.     pthread_mutex_init(&shared.mutex, NULL);
  95.     for (index = 0; index < NP; index++)
  96.     {
  97.         /* Create a new producer */
  98.         pthread_create(&idP, NULL, Producer, (void*)index);
  99.     }
  100.     /*create a new Consumer*/
  101.     for(index=0; index<NC; index++)
  102.     {
  103.         pthread_create(&idC, NULL, Consumer, (void*)index);
  104.     }
  105.  
  106.  
  107.  
  108.     pthread_exit(NULL);
  109. }
  110.  
Success #stdin #stdout 0s 5312KB
comments (?)
stdin
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Standard input is empty
stdout
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[P2] Producing 0 ...
[P2] Producing 1 ...
[C2] Consuming  0 ...
[C1] Consuming  1 ...
[P1] Producing 0 ...
[P1] Producing 1 ...
[C0] Consuming  0 ...
[C2] Consuming  1 ...
[P0] Producing 0 ...
[P0] Producing 1 ...
[C1] Consuming  0 ...
[C0] Consuming  1 ...
[P2] Producing 2 ...
[P2] Producing 3 ...
[C0] Consuming  2 ...
[C1] Consuming  3 ...
[P1] Producing 2 ...
[P1] Producing 3 ...
[P0] Producing 2 ...
[P0] Producing 3 ...
[C0] Consuming  2 ...
[C2] Consuming  3 ...
[C2] Consuming  2 ...
[C1] Consuming  3 ...
https://ideone.com/MssJVJ
language:
C (clang 8.0)
created:
14 days ago
visibility:
public

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