What is the purpose of a volatile member function in C++?

Question

What is the purpose of a volatile member function in C++?

Answer 1

EDIT:

This answer was posted when the question was about the volatile keyword. Question seems to have been changed by a third party.

ORIGINAL:

Volatile informs the compiler that it should not assume that the value it just put in the variable marked as volatile will be there next time it uses it... that it must check the current value before using it again.

One example is if the variable represents a memory location that might be changed by another process.

Here's an example (been ages since I did C++ so please forgive any minor syntax issues):

volatile int x;

int DoSomething()
{
    x = 1;

    DoSomeOtherStuff();

    return x+1; // Don't just return 2 because we stored a 1 in x.  
                // Check to get its current value
}