104 lines
2.4 KiB
C
104 lines
2.4 KiB
C
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#include <stdio.h>
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#include <stdlib.h>
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#include <pthread.h>
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#include <semaphore.h>
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#include <unistd.h>
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#define BUFFER_SIZE 10
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#define NUM_ITEMS 20 // items to be produced/consumed
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int buffer[BUFFER_SIZE];
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int in = 0;
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int out = 0;
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sem_t empty; // empty slots semaphore
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sem_t full; // available items semaphore
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pthread_mutex_t mutex; // mutex for shared vars
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void* producer(void* arg) {
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int item;
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for (int i = 0; i < NUM_ITEMS; i++) {
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item = i; // item is set to index
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// waiting for empty slot
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sem_wait(&empty);
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// critical section
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pthread_mutex_lock(&mutex);
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// item placement into buffer
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buffer[in] = item;
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printf("Produced: %d at index %d\n", item, in);
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in = (in + 1) % BUFFER_SIZE;
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// critical section exit
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pthread_mutex_unlock(&mutex);
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// empty slot available
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sem_post(&full);
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// production time sim using sleep
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sleep(1);
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}
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pthread_exit(NULL);
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}
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void* consumer(void* arg) {
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int item;
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for (int i = 0; i < NUM_ITEMS; i++) {
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// waiting for at least one item in the buffer
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sem_wait(&full);
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// critical section
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pthread_mutex_lock(&mutex);
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// item removal from buffer
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item = buffer[out];
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printf("Consumed: %d from index %d\n", item, out);
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out = (out + 1) % BUFFER_SIZE;
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// critical section exit
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pthread_mutex_unlock(&mutex);
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// empty slot
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sem_post(&empty);
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// consumption time sim using sleep
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sleep(2);
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}
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pthread_exit(NULL);
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}
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int main(void) {
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pthread_t producer_tid, consumer_tid;
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// semaphore init
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sem_init(&empty, 0, BUFFER_SIZE); // empty slots init
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sem_init(&full, 0, 0); // available items init
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// mutex init
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pthread_mutex_init(&mutex, NULL);
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// thread creator
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if (pthread_create(&producer_tid, NULL, producer, NULL) != 0) {
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perror("Failed to create producer thread");
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exit(EXIT_FAILURE);
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}
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if (pthread_create(&consumer_tid, NULL, consumer, NULL) != 0) {
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perror("Failed to create consumer thread");
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exit(EXIT_FAILURE);
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}
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// thread completion wait
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pthread_join(producer_tid, NULL);
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pthread_join(consumer_tid, NULL);
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// cleanup of semaphores and mutex
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sem_destroy(&empty);
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sem_destroy(&full);
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pthread_mutex_destroy(&mutex);
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return 0;
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}
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