A group of producers produce products and provide them to consumers for consumption. In order to enable the producer process and the consumer process to proceed concurrently, a buffer pool with n buffers is set between them, and the producer process puts the products into a buffer; Consumers can take products from a buffer to consume. Although all producer processes and consumer processes run in different ways, they must remain synchronized: consumers are not allowed to take products when a buffer is empty, and producers are not allowed to store products when a buffer is full.

int in = 0 , out = 0 ;

item buffer[n];

semaphore mutex = 1 ;

semaphore empty = n ;

semaphore full = 0 ;

 

//producer

void producer {

 

do {

 

item = produce_item();

wait(empty);

wait(mutex);

buffer[in] = insert_item(item);

in = ( in +1 ) % n ;

signal(mutex);

signal(full);

 

} while（1）

}

 

//consumer

void consumer{

 

do {

 

wait(full);

wait(mutex);

remove_item(item) = buffer[out] ;

out = ( in +1 ) % n ;

signal(mutex);

signal(empty);

consumer_item(item);

} while（1）

}

 

void main() {

 

cobegin

producer();consumer();

coend

 

}