When to use PImpl idiom c++?

The PImpl Idiom (Pointer to IMPLementation) is a technique used for separating implementation from the interface. It minimizes header exposure and helps programmers to reduce build dependencies by moving the private data members in a separate class and accessing them through an opaque pointer.

Is PIMPL good?

It is a good paradigm for classic OOP (inheritance based), but not for generic programming (specialization based). You have to be more precise: there’s absolutely no problem when using PIMPL classes as template type arguments.

What is C++ Pimpl?

The pimpl idiom is a modern C++ technique to hide implementation, to minimize coupling, and to separate interfaces. Pimpl is short for “pointer to implementation.” You may already be familiar with the concept but know it by other names like Cheshire Cat or Compiler Firewall idiom.

When should you not use Pimpl?

You shouldn’t use PIMPL when virtual calls or any sort of indirection cost your users too much in operation time of their programs:

1. Sequences of repeated small functions calls (and you can’t remove it from API level).
2. Creating and deleting huge amount of small objects (and you can’t remove it from API level).

Why do we need forward declaration in C++?

A forward declaration allows us to tell the compiler about the existence of an identifier before actually defining the identifier. In the case of functions, this allows us to tell the compiler about the existence of a function before we define the function’s body.

What is handle in C?

The term handle is used to mean any technique that lets you access to another object. A handle can be a pointer, a reference, a pointer to a pointer, etc.. But sure its related to classes, objects etc. So handle need not always be a pointer to structure.

Can a pointer be void?

A void pointer is a pointer that has no associated data type with it. A void pointer can hold address of any type and can be typcasted to any type.