How to avoid deadlocks?

Question

When using multiple threads, shared memory needs to be locked by critical sections. However, using critical sections causes potential deadlocks. How can they be avoided?

Answer 1

You can avoid critical sections by using message passing instead (synchronous and asynchronous calls). When using synchronous calls, you still have to make sure not to make a circular call, in which thread A asks thread B a question, and B needs to ask A a question to be able to respond.

Another option is to make asynchronous calls instead. However, it is more difficult to get return values.

Note: Indeed, a message passing system is implemented using a critical section that locks the call queue, but it is abstracted away.