Static Member Functions
Static member functions are considered to have class scope. In contrast to nonstatic member functions, these functions have no implicit this argument; therefore, they can use only static data members, enumerators, or nested types directly. Static member functions can be accessed without using an object of the corresponding class type. Consider this example:
Example
// static_member_functions.cpp
#include <stdio.h>
class StaticTest
{
private:
static int x;
public:
static int count()
{
return x;
}
};
int StaticTest::x = 9;
int main()
{
printf_s("%d\n", StaticTest::count());
}
9
Comments
In the preceding code, the class StaticTest contains the static member function count. This function returns the value of the private class member but is not necessarily associated with a given object of type StaticTest.
Static member functions have external linkage. These functions do not have this pointers. As a result, the following restrictions apply to such functions:
They cannot access nonstatic class member data using the member-selection operators (. or –>).
They cannot be declared as virtual.
They cannot have the same name as a nonstatic function that has the same argument types.
备注
The left side of a member-selection operator (. or –>) that selects a static member function is not evaluated. This can be important if the function is used for its side effects. For example, the expression SideEffects().CountOf() does not call the function SideEffects.