Practical C Programming

Avoiding a deadlock

A deadlock can be avoided if the threads are allowed to acquire the locks in a sequence. Let's suppose that a thread acquires the lock for a resource and wants to acquire the lock for a second resource. Any other thread that tries to acquire the first lock will be asked to wait, as it was already acquired by the first thread. Therefore, the second thread will not be able to acquire the lock for the second resource either, since it can only acquire locks in a sequence. However, our first thread will be allowed to acquire the lock to the second resource without waiting.

Applying a sequence to the locking of resources is the same as allowing only one thread to acquire resources at a time. The other threads will only be able ...