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  1. #include <iostream>
  2. #include <sys/ipc.h>
  3. #include <sys/shm.h>
  4. #include <sys/types.h>
  5. #include <semaphore.h>
  6. #include <fcntl.h>
  7. #include <unistd.h>
  8.  
  9. #define SHM_SIZE 1024  // Shared memory size
  10.  
  11. struct SharedMemory {
  12.     sem_t mutex;
  13.     sem_t full;
  14.     sem_t empty;
  15.     int buffer;
  16. };
  17.  
  18. void producer() {
  19.     key_t key = ftok("shmfile", 65);
  20.     int shmid = shmget(key, sizeof(SharedMemory), 0666 | IPC_CREAT);
  21.     SharedMemory* shm = (SharedMemory*)shmat(shmid, nullptr, 0);
  22.  
  23.     sem_init(&shm->mutex, 1, 1);
  24.     sem_init(&shm->full, 1, 0);
  25.     sem_init(&shm->empty, 1, 1);
  26.  
  27.     for (int i = 1; i <= 5; ++i) {
  28.         sem_wait(&shm->empty);
  29.         sem_wait(&shm->mutex);
  30.  
  31.         shm->buffer = i;
  32.         std::cout << "Produced: " << i << std::endl;
  33.  
  34.         sem_post(&shm->mutex);
  35.         sem_post(&shm->full);
  36.         sleep(1);
  37.     }
  38. }
  39.  
  40. void consumer() {
  41.     key_t key = ftok("shmfile", 65);
  42.     int shmid = shmget(key, sizeof(SharedMemory), 0666 | IPC_CREAT);
  43.     SharedMemory* shm = (SharedMemory*)shmat(shmid, nullptr, 0);
  44.  
  45.     for (int i = 1; i <= 5; ++i) {
  46.         sem_wait(&shm->full);
  47.         sem_wait(&shm->mutex);
  48.  
  49.         int data = shm->buffer;
  50.         std::cout << "Consumed: " << data << std::endl;
  51.  
  52.         sem_post(&shm->mutex);
  53.         sem_post(&shm->empty);
  54.         sleep(1);
  55.     }
  56.  
  57.     sem_destroy(&shm->mutex);
  58.     sem_destroy(&shm->full);
  59.     sem_destroy(&shm->empty);
  60.     shmctl(shmid, IPC_RMID, nullptr);
  61. }
  62.  
  63. int main() {
  64.     pid_t pid = fork();
  65.     if (pid > 0) {
  66.         producer();
  67.     } else {
  68.         consumer();
  69.     }
  70.     return 0;
  71. }
Success #stdin #stdout 0.01s 5288KB
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stdin
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Standard input is empty
stdout
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Produced: 1
Consumed: 1
Produced: 2
Consumed: 2
Produced: 3
Consumed: 3
Produced: 4
Consumed: 4
Produced: 5
Consumed: 5
https://ideone.com/qOrzTr
language:
C++14 (gcc 8.3)
created:
10 days ago
visibility:
public

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