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
