Why Doesn't C Have Virtual Constructors?

Why a Virtual Constructor is Not Part of C 's Toolkit

Unlike many programming languages, C does not incorporate virtual constructors in its framework. Unveiling the rationale behind this design decision requires delving into the inherent characteristics of virtual calls and constructors.

Virtual calls enable function invocation based on known interfaces rather than the specific object type. This capability proves invaluable for orchestrating polymorphic behavior. However, when creating an object, precise knowledge of its exact type is paramount.

Bjarne Stroustrup, the architect of C , succinctly articulates this concept: "A virtual call is a mechanism to get work done given partial information ... To create an object, you need complete information ... Consequently, a 'call to a constructor' cannot be virtual."

While a virtual constructor may seem desirable, its absence does not preclude achieving similar outcomes. The aforementioned FAQ entry suggests a practical approach to emulate the behavior of a virtual constructor without resorting to its explicit implementation.

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