On Tuesday, 6 March 2018 at 21:20:22 UTC, Henrik wrote:
Does anyone know if D is using the vtable implementation for virtual functions just like most C++ compilers? If yes, can someone explain the advantages of this strategy? A function pointer in C is regarded as expensive because of missing inlining, but a double indirection through a vtable just looks insane - if there aren't really good reasons for such an implementation. Does it make class inheritance or class polymorphism much simpler to implement or what is the reason?

I have worked with C in embedded systems for many years now, and for our modern Linux systems we are using a combination of C and Java today. Java for parts where memory safety is more important than speed/determinism, and C for the critical real time parts. There should exist a language between these worlds, where we can achieve memory safety at relatively small costs. C++ is not really an alternative, and D looks much more pleasant for us C programmers than for example Rust.

p0nce[1] has a link to an excellent article explaining in detail how the implementation of the vtable, single inheritance with interfaces work. The article isn't about D per se but D classes use the same mechanism.

[1]: https://p0nce.github.io/d-idioms/#Inside-the-D-Object-Model

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