How is one producer or consumer accessing the buffer?
One or more threads generate data and put it into a buffer One or more threads take data items from the buffer, one at time Only one producer or consumer may access the buffer at any one time Variants, of increasing difficulty: Single producer & single consumer Multiple producers & single consumer Multiple producers & multipole consumers
How does the producer-consumer problem work in prodcons?
See prodcons0.cfor a complete program using a circular (ring) buffer and no other form of synchronization. This solution works for a single producer and a single consumer, because the shared variables inand outhave only a single reader and a single writer It is a very important mechanism for those situations where it works, because:
What happens when a consumer is unblocked on pthread _ mutex _ lock?
For example, tn the figure the consumer that was blocked on a call to pthread_mutex_lockwill be unblocked and allowed to enter the room. The thread that is waiting in the side room will wait there until it wakes up, at which point it will try to get back into the protected room.
How does pthread _ cond _ wait ( & m ) work?
It cannot proceed, so it call pthread_cond_wait (&In_CV, &M);. The effect is as if the calling thread leaves the protected room and goes into a side room, then goes to sleep. When the thread leaves the room, the guard (the mutex) notices and will now allow another thread into the room.
How are producer and consumer related in multithreaded programming?
A producer must wait until the buffer has space before it can put something in, and a consumer must wait until something is in the buffer before it can take something out. A condition variable represents a queue of threads waiting for some condition to be signaled.
Which is an example of the producer / consumer problem?
The Producer/Consumer Problem. A condition variable represents a queue of threads waiting for some condition to be signaled. Example 4-11 has two such queues, one ( less) for producers waiting for a slot in the buffer, and the other ( more) for consumers waiting for a buffer slot containing information.