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.
D uses vtables.
It's a tradeoff between having double indirection and bloating
each instance with the function pointers. In cases where
bloating isn't a problem, I just explicitly add normal function