What Does the Scope Resolution Operator (::) Do Without a Scope?

The Scope Resolution Operator in a Void

The scope resolution operator (::) is typically used to access members of a specific scope. However, it can also be used without a scope, such as in the following example:

::foo();

Purpose of the Scope Resolution Operator without a Scope

When used without a scope, the scope resolution operator refers to the global scope. This means that it accesses symbols that are not defined within any specific class or namespace.

Example of Using the Scope Resolution Operator without a Scope

Consider the following code:

void bar();    // this is a global function

class foo {
    void some_func() { ::bar(); }    // this function is calling the global bar() and not the class version
    void bar();                      // this is a class member
};

In the above example, there are two bar() functions: one is a global function, and the other is a class member function. If you call bar() from within the class member function some_func(), it would call the class member function. However, by using ::bar(), you can explicitly access the global bar() function.

In summary, the scope resolution operator without a scope refers to the global scope, allowing you to access global symbols from any context. It is particularly useful when you need to disambiguate between multiple symbols with the same name or when you need to access global symbols from within a class member function.

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