What's a better way to implement a semaphore or mutex lock mechanism?

Question

I'm new to OS, and I read a question on textbook today.

Instead of doing this:

bool AquireLock(int mutex)
{
    while (mutex > 0); // do nothing until mutex == 0
    mutex++;
    return true;
}

This way requires lots of meaningless CPU cycle, is there a better way to implement this?