My non-member static function allows changing and creating of non static variables

Question

this is the code snippet

static chck()//tracking how many times main has been called
{
    static a=0;
    int y=0;//this is not supposed to work
    cout<<"Total time main has been called:  ";
    a++;
    return a;
}

our teacher told us that static functions can't change or create non static variables but it works for me ,why?

`static` **member** functions cannot use/change non-static **data members** because that makes no sense. The function isn't called on any object to use the members of. This `static` just means the function has internal linkage. It's completely different. — chris, Jul 03 '14 at 16:56
Consider reading through http://stackoverflow.com/questions/1358400/what-is-external-linkage-and-internal-linkage-in-c — chris, Jul 03 '14 at 17:07

score 1 · Answer 1 · answered Jul 03 '14 at 17:05

In this case "y" is a stack variable which this function can access.

The theory is static member functions (static Methods in a class) cannot access non static member variables (non static variables in the class) as there is no object as "this" inside a static member function.

score 0 · Answer 2 · answered Jul 03 '14 at 17:00

static may well be the most overused keyword in c++. Your first use of it refers to the linkage of chck(), i.e. it has internal linkage. Your second use makes a static with respect to calls to ckch(), i.e. it's value will be preserved between calls. You are think of static member functions of a class that can't access non-static data members, i.e. those data members that are created per object instance.

My non-member static function allows changing and creating of non static variables

2 Answers2