On Thursday, 27 June 2019 at 17:00:01 UTC, Rémy Mouëza wrote:
I though support for C++ allocation had improved. In a recent
release, there was the addition of core.stdcpp.new, but I
didn't try it out:
It seems at this moment these operators only supported on Windows.
Are there still pitfalls to be wary of?
- new/delete (not entirely impossible, but requires to dig in
compiler/library internals, generally fragile and not portable,
not even mention that deciphering STL code is just meh...),
though many libraries provides their own allocator/deallocator
functions and some even provides pluggable hooks to use.
- Member functions pointers
- Multiple inheritance (tbh this is considered a bad practice
anyway and chances to encounter it relatively small)
- Exceptions? (except maybe on Windows, because of SEH)
- Template instantiations code gen(this basically requires to
implement entire C++ compiler), what this means is that if the
concrete template instance isn't used in a library you use you
have to make dummy C++ function that forces compiler to emit the
code for it.
Possible, but annoying:
- Functions with ref parameters
- Functions with const pointers to mutable data parameters
ex: float calcStuff(float * const arr, size_t len);
It doesn't make sense in D, and I doubt there is much sense in
C++ as well (except maybe to convey the meaning that this
function won't try to free data).
So the workaround of course is to slap pragma mangle, which of
course requires manually getting the mangled name for the
On Windows using MS compiler for the example above the mangled
name will look like
float calc(float * const arr); // ?calc@@YAMQEAM@Z
and for non const
float calc(float * arr); // ?calc@@YAMPEAM@Z
so it is possible to do something like this
float calc(float * arr);
- Some operator overloads also needs pragma mangle treatment.
- Incomplete/buggy mangling support, especially annoying with
templates. Same treatment.
Maybe I've missed something else though, but anything not on the
list usually works without surprises. And thanks to string
namespaces it is now such a relief to use.