nonstandard extension used : 'identifier' : 'static' should not be used on member functions defined at file scope
A static member function was defined at file scope. Static member functions should be declared with external linkage.
This is a warning when Microsoft extensions are used (/Ze) and is an error when Microsoft extensions are disabled (/Za).
The following is an example of this error:
class C
{
static void func();
};
static void C::func(){}; // warning