Why constructor cannot be virtual in c

There are some nonprintable characters that have crept in to the citation for Lockheed Martin Pages Boards. Page tree. Browse pages. A t tachments 0 Page History People who can view. Jira links. Created by Stephen C. Dewhurst , last modified by Anirban Gangopadhyay on Jul 19, Noncompliant Code Example In this noncompliant code example, the base class attempts to seize and release an object's resources through calls to virtual functions from the constructor and destructor.

Aaron Ballman. Permalink Mar 13, David Svoboda. Fixed, thanks. Permalink Mar 14, Chris Poerschke. How is compile-time dispatching done during runtime? The FAQ entry goes on to give the code for a way to achieve this end without a virtual constructor. Login using GitHub Register. Ask a Question. Please log in or register to add a comment. Please log in or register to answer this question.

Hear it from the horse's mouth. Related questions. Why do we need virtual memory? So my understanding is that every process has its own virtual memory space ranging from 0x0 to 0xFF These virtual addresses correspond to addresses I understand the need for a virtual destructor.

The class User is utility class trying to make use of the hierarchy. The main function is consuming Base hierarchy functionality via User class. The User class constructor is creating Derived1 object, always. Recompiling is bad way of design, so we can opt for the following approach. Before going into details, let us answer, who will dictate to create either of Derived1 or Derived2 object? Clearly, it is the consumer of User class.

In simple words, if the library updates the Base class hierarchy with new class Derived3. How can the User class creates Derived3 object? The problem is with the creation of objects.

Addition of new class to the hierarchy forcing dependents of User class to recompile. By delegating the object creation to class hierarchy or to a static function we can avoid the tight coupling between User and Base hierarchy. It delegates that responsibility to Base , and provides an input in the form of ID. If the library adds new class Derived4 , the library modifier will extend the if-else ladder inside Create to return proper object.

Consumers of User need not recompile their code due to extension of Base. Note that the function Create used to return different types of Base class objects at runtime.

It acts like virtual constructor, also referred as Factory Method in pattern terminology.