Hi I'm trying to write an algorithm for solving the producer-consumer problem and I've hit a roadblock. This is the output I am getting from my code:
Producing: 6 6 0 0 0 0 0 0 0 0 0 END
and then the program exits. I'm not sure where I went wrong? Did I do something wrong in creating a circular buffer?
#include <iostream>
#include <pthread.h>
#include <semaphore.h>
#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>
#include <string>
#include <fstream>
using namespace std;
#define BUFFER_SIZE 10
void *produce(void *);
void *consume(void *);
int produceItem(void);
void insertItem(int item);
void removeItem(void);
void printBuffer(void);
int head = 0;
int tail = 0;
int item;
int bufferCount = 0;
pthread_t producer, consumer;
pthread_cond_t Buffer_Not_Full=PTHREAD_COND_INITIALIZER;
pthread_cond_t Buffer_Not_Empty=PTHREAD_COND_INITIALIZER;
pthread_mutex_t lock;
sem_t sem_filledSlots;
sem_t sem_emptySlots;
int buffer[BUFFER_SIZE];
int main() {
int emptyCount;
int item;
srand (time(NULL));
sem_init(&sem_filledSlots, 0, 0);
sem_init(&sem_emptySlots, 0, BUFFER_SIZE);
sem_getvalue(&sem_emptySlots, &emptyCount);
pthread_create (&producer, NULL, &produce, NULL);
pthread_create (&consumer, NULL, &consume, NULL);
return 0;
}
void *produce(void *)
{
for(int i = 0; i <15; i++)
{
item = produceItem();
sem_wait(&sem_emptySlots);
pthread_mutex_lock(&lock);
printf("Producing: %d \n", item);
buffer[head] = item;
head = (head + 1) % BUFFER_SIZE;
printBuffer();
pthread_mutex_unlock(&lock);
sem_post(&sem_filledSlots);
}
}
void *consume(void *)
{
for(int i = 0; i <15; i++)
{
sem_wait(&sem_filledSlots);
pthread_mutex_lock(&lock);
printf("Consuming %d \n", buffer[tail]);
buffer[tail] = 0;
tail = (tail + 1) % BUFFER_SIZE;
bufferCount--;
printBuffer();
pthread_mutex_unlock(&lock);
sem_post(&sem_emptySlots);
}
}
int produceItem(void)
{
int x = (rand()%11 + 1);
return x;
}
void printBuffer(void)
{
for(int i = 0; i <BUFFER_SIZE; i++)
{
printf("%d ", buffer[i]);
}
printf("END \n");
}
