Re: Interfacing with basic C++ class
On Wednesday, 28 September 2022 at 20:41:13 UTC, Ali Çehreli wrote: [...] Ali Thank you, that is perfect! However that begs the following observation: it would be rather hard to link to a C++ library only by means of 'extern (C++)' if one should slightly rearrange C++ code as well. This sounds like it is rather obvious to the community, actually, but I am a recent addition to D language :) Do you know that this is documented somewhere? The examples in the official docs are rather limited, maybe studying a github with previous work might help. Cheers
Re: importC and cmake
On Wednesday, 28 September 2022 at 06:04:36 UTC, zjh wrote:
On Wednesday, 28 September 2022 at 05:29:41 UTC, Chris Piker
wrote:
`Xmake` is indeed simpler.
`Xmake` is really nice!
zjh
Sorry to go off topic for a moment, but do you happen to know how
to tell xmake that my project is C only, and thus it shouldn't
add the /TP flag to cl.exe? The obvious statement:
```lua
set_languages("c99")
```
doesn't accomplish that task.
Thanks for the help,
Re: importC and cmake
On Thursday, 29 September 2022 at 20:56:50 UTC, Chris Piker wrote:
```lua
set_languages("c99")
```
Try:
`add_cxflags` or `add_files("src/*.c")` or
`set_languages("c")` or
`set_languages("c11")` .
or ,use `-l` to set language.
```cpp
xmake create -l c -t static test
```
Re: Interfacing with Rust
On Thursday, 29 September 2022 at 16:07:59 UTC, mw wrote: On Thursday, 29 September 2022 at 16:02:43 UTC, Ruby The Roobster wrote: Is there any way one can interface with Rust, such as with a struct, or a function? I know that rust has an extern keyword, but I can't get it to work. https://code.dlang.org/packages/rust_interop_d Read the notes on memory management: Only pass pointers as u64 as value type. This isn't the issue. I can't interface anything, period.
Re: Interfacing with basic C++ class
On Wednesday, 28 September 2022 at 19:57:10 UTC, Riccardo M wrote:
I think I am stuck in the easiest of the issues and yet it
seems I cannot get around this.
I have a C++ file:
```
class MyClass {
public:
int field;
MyClass(int a) : field(a) {}
int add(int asd) {
return asd + 1;
}
};
```
Ali is correct. However, you don’t have to change anything on the
C++ side, just map C++ class to D struct:
```D
extern(C++, class) {
struct MyClass {
public:
int field;
@disable this();
int add(int asd); //struct fields are always `final`
}
MyClass* instantiate(int asd); //mind the *
}
```
Re: Interfacing with basic C++ class
On 9/29/22 01:28, Riccardo M wrote: > if one should > slightly rearrange C++ code as well. Right. Additionally, the order of members must match (I am pretty sure, which means I am not :p). > I am a recent addition to D > language :) Welcome! :) > Do you know that this is documented somewhere? The examples in the > official docs are rather limited Manu Evans said at DConf 2022 that the documentation is very lacking compared to actual capability. People who know should update the docs. Ali
Re: Interfacing with basic C++ class
On Thursday, 29 September 2022 at 11:13:15 UTC, Ogi wrote:
Ali is correct. However, you don’t have to change anything on
the C++ side, just map C++ class to D struct:
[...]
Thanks, this works perfectly.
Now i see that I can even instantiate directly from D, calling
the default ctor, calling the custom ctor or even overriding the
custom ctor in D (the fact that ctors could be called, in
contrast with docs, was in fact hinted at DConf 2022 as suggested
by Ali).
So it turns out that D's structs are a much better match for
C++'s classes in this case. But why is this? Can you elaborate?
It must have to do with the fact that D structs are passed by
value?
Now this D code runs as expected:
```
// D
extern(C++, class) {
struct MyClass {
public:
int field;
this(int a);
int add(int asd);
}
MyClass* instantiate(int asd);
}
void main()
{
import std : writeln;
auto myclass = instantiate(100); //actually, instantiation
through C++ is not required any longer
assert(myclass.field == 100);
auto myclass2 = new MyClass;
assert(myclass2.field == 0);
auto myclass3 = new MyClass(50);
assert(myclass3.field == 50);
assert(myclass3.add(40) == 90);
}
```
However the 'add' function only links correctly if C++ has the
function body defined outside of its class.
```
// C++
int MyClass::add(int asd) {
return field + asd;
}
```
If the function is defined inside its class, it is an undefined
reference at link time. Once again I ask for clarifications and
workarounds, if possible.
Thanks
Interfacing with Rust
Is there any way one can interface with Rust, such as with a struct, or a function? I know that rust has an extern keyword, but I can't get it to work.
Re: Interfacing with Rust
On Thursday, 29 September 2022 at 16:02:43 UTC, Ruby The Roobster wrote: Is there any way one can interface with Rust, such as with a struct, or a function? I know that rust has an extern keyword, but I can't get it to work. https://code.dlang.org/packages/rust_interop_d Read the notes on memory management: Only pass pointers as u64 as value type.
