How Do C \'s `->*` and `.*` Operators Facilitate Member Function Invocation?

*` and `.*` Operators Facilitate Member Function Invocation? " />

Unveiling the Mystery of Pointer-to-Member Operators -> and .: A Clarity-Enhancing Explanation

While discussions surrounding pointer-to-member operators -> and . abound, a comprehensive grasp of their nature remains elusive. To address this, let's embark on a journey to demystify these operators, understanding their roles in member function invocation.

What are -> and .?

Unlike the conventional pointer-to-member operator -> and the member access operator ., -> and . facilitate the invocation of member functions through member function pointers. They enable us to access and execute member functions indirectly.

When to Use ->* and .

• ->: When you have a pointer to a member function and an object pointer, use -> followed by parentheses containing the member function pointer. This technique is particularly useful when you have a pointer to an object and want to invoke a particular member function via a pointer-to-member.
• .:*: When you have a member function pointer and an object, simply use preceded by parentheses containing the member function pointer. In this scenario, you have an object instance rather than a pointer to an object.

Code Illustrating the Difference

Consider the following C code snippet:

struct X {
    void f() {}
    void g() {}
};

typedef void (X::*pointer)();
pointer somePointer = &X::f;
X x;
X* px = new X;

// Calling the member function using ->*
(px->*somePointer)();

// Calling the member function using .
(x.*somePointer)();

In this example:

• (px->*somePointer)(); calls the member function f of the X object pointed to by px.
• (x.*somePointer)(); calls the member function f of the X object x.

By employing -> or ., you can flexibly invoke member functions based on whether you have an object pointer or an object instance. These operators provide a versatile mechanism for indirect member function access, enhancing the flexibility and reusability of your C code.

The above is the detailed content of How Do C \'s `->*` and `.*` Operators Facilitate Member Function Invocation?. For more information, please follow other related articles on the PHP Chinese website!