The volatile C ++ keyword with a global shared variable accessed by a function

Question

I have a multithreaded C ++ application.

Now I know that for global shared variables you should use volatile in some cases when checking the state of a variable, otherwise the compiler could assume that the value of the variable never changes (in this thread).

What if, instead of checking the status of a variable, I call a method that returns the value of the variable? For instance:

static int num = 0;

...

void foo()
{
   while(getNum() == 0)
   {
      // do something (or nothing)
   }
}

Should I make num volatile variable? or does the compiler acknowledge that since I use a method to access this num variable, it will not cache the result?

Does anyone have any ideas?

Thanks in advance,

~ Julian

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