On Friday, 25 April 2025 at 16:59:10 UTC, sfp wrote:
On Friday, 25 April 2025 at 05:24:55 UTC, evilrat wrote:
both f() would be marked `final` in D which will tell it is
'nonvirtual override', and then you will have more headache.
I don't care if I have a headache or not, I need to wrap the
C++ code and I can't change it. Needs must.
but you already having it :)
I tried this already. E.g.:
```
extern(C++) class A {
final void f() {}
void g() {} // need at least one virtual function...
}
extern(C++) class B: A {
final void f() {}
}
void main() {}
```
and dmd complains about it:
```
Error: function `main.B.f` cannot override `final` function
`main.A.f`
```
Well then, time to resolve to some craftery.
you can do alias and use pragma mangle to fix mangling.
enjoy.
```d
import std.string;
import std.conv : text;
string fixMangle(alias sym, string name)() {
version(Windows) {
return sym.mangleof.replace(__traits(identifier, sym), "f");
}
else version(Posix) {
return sym.mangleof.replace(__traits(identifier,
sym).length.text ~ __traits(identifier, sym), name.length.text ~
name );
}
else
static assert (0, "unsupported system");
}
extern(C++, struct) class A {
// by default will look like this on windows "?f_A@A@@QEAAX"
// can be fixed with the help of pragma mangle & replace
//pragma(mangle, f.mangleof.replace("f_A", "f"))
// but here is more system agnostic way
pragma(mangle, fixMangle!(f_A, "f"))
final void f_A() {}
alias f = f_A;
final void a();
void g() { f(); } // need at least one virtual function...
}
// defined as f_A but now will be properly reflected as
"?f@A@@QEAAX"
// or for linux target `ldc2 foo.d
-mtriple=x86_64-linux-unknown-unknown -c` "_ZN1A1fEv" (here it
is named 1f)
pragma(msg, A.f.mangleof);
pragma(msg, B.f.mangleof);
extern(C++, struct) class B: A {
pragma(mangle, f.mangleof.replace("f_B", "f"))
final void f_B() {}
alias f = f_B;
override void g() { f(); }
}
void main() {}
```
