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c++multithreadingthread-safetymutexboost-mutex

Mutex on part of class

Is it possible to use mutexes on parts of a class ?

Like :

class A{
    int a;
    int b;
    boost::mutex Mutex_for_a;
    boost::mutex Mutex_for_b;
}

and then use the right mutex to perform the right operation. I know this is technically possible but I don't know if it can lead to problems.

Solution

  • I know this is technically possible but I don't know if it can lead to problems.

    This is certainly possible. However, if not handled carefully, things like this can lead to deadlocks:

    A::use_a() { std::lock_guard lck{ Mutex_for_a }; use_b(); ... }
A::use_b() { std::lock_guard lck{ Mutex_for_b }; use_a(); ... }

    So you have to make sure that if your class design allows to have both mutexes locked at the same time, the locking order is consistent everwhere (or better use std::scoped_lock).