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Is it true that one process can lock a mutex and another process can unlock it?
A process that is waiting for access to a critical section does not consume processor time. It is possible for one process to lock the mutex and for another process to unlock it. FALSE. On of the most common problems faced in concurrent processing is the producer/consumer problem.
What is the purpose of using mutex lock in pthreads?
Mutex lock will only be released by the thread who locked it. So this ensures that once a thread has locked a piece of code then no other thread can execute the same region until it is unlocked by the thread who locked it. Hence, this system ensures synchronization among the threads while working on shared resources.
What is mutex lock and unlock?
All lock and unlock operations on the mutex follow a single total order, with all visible effects synchronized between the lock operations and previous unlock operations on the same object. If the mutex is not currently locked by the calling thread, it causes undefined behavior.
Why do we use mutex locks?
Mutex or Mutual Exclusion Object is used to give access to a resource to only one process at a time. The mutex object allows all the processes to use the same resource but at a time, only one process is allowed to use the resource. Mutex uses the lock-based technique to handle the critical section problem.
What happens when a mutex is locked?
Locks a mutex object, which identifies a mutex. Mutexes are used to protect shared resources. If the mutex is already locked by another thread, the thread waits for the mutex to become available. The thread that has locked a mutex becomes its current owner and remains the owner until the same thread has unlocked it.
What happens if you unlock a unlocked mutex?
When the lock count reaches zero, the mutex becomes available for other threads to acquire. If a thread attempts to unlock a mutex that it has not locked or a mutex which is unlocked, an error will be returned.
What happens if a mutex is already locked C++?
If the mutex is currently locked by another thread, execution of the calling thread is blocked until unlocked by the other thread (other non-locked threads continue their execution). If the mutex is currently locked by the same thread calling this function, it produces a deadlock (with undefined behavior).
What happens if a mutex is already locked?