Using semaphores modify your code to allow proper synchronization between multiple producers and multiple consumers running concurrently.

Include the thread ID of the producers and consumers in the print statements. Pthread_self( ) function returns the pthread ID of the calling thread. Submit a copy of your source code and a screenshot of your output.

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#include

#include

#include

#define BUFF_SIZE 20

char buffer[BUFF_SIZE];

int nextIn = 0;

int nextOut = 0;

//used for synchronization producer should be blocked if the buffer is full

sem_t empty_slots;

//used for synchronization consumer should be blocked if the buffer is empty

sem_t full_slot;

//used for mutual exclusion enforces mutual exclusion on the shared buffer

sem_t mutex;

void Put(char item)

{

...

buffer[nextIn] = item;

nextIn = (nextIn + 1) % BUFF_SIZE;

printf("Producing %c ... ", item);

...

}

void * Producer()

{

int i;

for(i = 0; i < 15; i++)

{

sleep(rand()%6);

Put((char)('A'+ i % 26));

}

}

void Get(char item)

{

...

item = buffer[nextOut];

nextOut = (nextOut + 1) % BUFF_SIZE;

printf("Consuming %c ... ", item);

...

}

void * Consumer()

{

int i;

char item;

for(i = 0; i < 15; i++)

{

sleep(rand()%6);

Get(item);

}

}

void main()

{

/* Initialize semaphores */

pthread_t pid, cid;

pthread_create(&pid, NULL, Producer, NULL);

pthread_create(&cid, NULL, Consumer, NULL);

// create more consumer & producer threads.

pthread_join(pid, NULL);

pthread_join(cid, NULL); }