Redundant Mutex - Is an atomic object a substitute for a mutex?, ¿Does Mutex generate atomicity like atomic objects?

Question

If I use atomic objects, I no longer need mutex (critical sections), right? or am I wrong?.

If I am wrong, could you give me a simple example (if possible in code) of when to use both, please?

¿Does Mutex generate atomicity like atomic objects?

Answer 1

If I am wrong, could you give me a simple example (if possible in code) of when to use both, please?

Ecample one, atomic:

std::atomic<bool> flag = false;

flag = true; // now flag can be checked from another thread

Example two. mutex:

SomeData *pointer1 = nullptr;
SomeOtherData *pointer2 = nullptr;

{
    std::scoped_lock<std::mutex> lock( mux );
    if( pointer1 && pointer2 ) {
         doSomethingWithData( pointer1, pointer2 );
    }
}

Examples are simplified of course, but should give you an idea.