Re: A question about C++ interop
On Sunday, 29 March 2020 at 17:32:59 UTC, kinke wrote:
On Sunday, 29 March 2020 at 15:20:52 UTC, YD wrote:
So what do I need to declare in the D file for it to match the
library entry? Thanks!
This is similar to
https://issues.dlang.org/show_bug.cgi?id=19260, and can be
worked around the same way by messing manually with the mangled
name, if you can't adapt the C++ side. The actual problem is
that you can't express a mutable reference to a const class
object (as opposed to a struct) in D (`const Y` is a const
reference to a const Y object).
(This problem somehow does not appear on Linux where the
library file is compiled with gcc, though)
The Itanium C++ mangling doesn't differentiate between:
void foo(const Y *); // what you have on the C++ side
void foo(const Y * const); // corresponds to D `void foo(const
Y)`
Thanks! I tried this:
class X {
version(Windows) {
pragma(mangle, X.call.mangleof.replace("QBV","PBV"))
final void call(const(Y)) const;
} else {
final void call(const(Y)) const;
}
}
and it worked. Thanks very much again!
Re: A question about C++ interop
On Sunday, 29 March 2020 at 15:20:52 UTC, YD wrote: So what do I need to declare in the D file for it to match the library entry? Thanks! This is similar to https://issues.dlang.org/show_bug.cgi?id=19260, and can be worked around the same way by messing manually with the mangled name, if you can't adapt the C++ side. The actual problem is that you can't express a mutable reference to a const class object (as opposed to a struct) in D (`const Y` is a const reference to a const Y object). (This problem somehow does not appear on Linux where the library file is compiled with gcc, though) The Itanium C++ mangling doesn't differentiate between: void foo(const Y *); // what you have on the C++ side void foo(const Y * const); // corresponds to D `void foo(const Y)`
Re: A question about C++ interop
On Sunday, 29 March 2020 at 15:20:52 UTC, YD wrote: On Sunday, 29 March 2020 at 01:50:24 UTC, evilrat wrote: [...] Thanks, dummy placeholder works. But there is a new problem on Windows, let's say there are two classes in C++: [...] Actually I found that if I create a C wrapper like extern "C" void X_call(X const *, Y const *); then it will work. So I have a workaround now. However, out of curiosity, is there a way to do this directly without C wrapper? Thanks.
Re: A question about C++ interop
On Sunday, 29 March 2020 at 01:50:24 UTC, evilrat wrote:
...
Same here, STL bindings is not yet finished. If you don't need
that method specifically, just replace it with a dummy. Or make
your own bindings.
Thanks, dummy placeholder works. But there is a new problem on
Windows, let's say there are two classes in C++:
class Y {
...
};
class X {
public:
void call(Y const * y) const;
};
on Windows, the library file (compiled with Visual C++) contains
an entry like this:
16C 0020 SECT4 notype ()External |
?call@X@@QBEXPBVY@@@Z (public: void __thiscall X::call(class Y
const *)const )
Then I declare it in D like this:
extern(C++) {
class Y {
...
}
class X {
final void call(const(Y) y) const;
}
}
The object file for this D code (compiled with ldc2) will contain
an entry like this:
0A7 UNDEF notype External |
?call@X@@QBEXQBVY@@@Z (public: void __thiscall X::call(class Y
const * const)const )
So there is a subtle difference in the signature, and the linker
refuses to resolve the symbol.
I tried "const Y y", "const(Y*) y", and "ref const(Y) y", but
none of them manages to match the library file entry.
(This problem somehow does not appear on Linux where the library
file is compiled with gcc, though)
So what do I need to declare in the D file for it to match the
library entry? Thanks!
Re: Find the heir.
On Sunday, 29 March 2020 at 14:04:53 UTC, TodNaz wrote:
Hello!
class A
{
...
}
class B : A
{
...
}
class C : A
{
...
}
A example1;
B example2 = new B(...);
A = example2;
auto heir = A.whoheir(); ///
The question in this code is: is it possible to track the class
inheritor? Or is it beyond D?
Sorry if the question is fool ...
The question is a bit unclear - what is whoheir expected to
return? This is one way that may or may not fulfill your
requirements:
module foo;
class A {
string whoheir() {
return typeid(this).name;
}
}
class B : A {}
class C : A {}
unittest {
A a = new B();
assert(a.whoheir == "foo.B");
a = new C();
assert(a.whoheir == "foo.C");
}
--
Simen
Re: Find the heir.
On Sunday, 29 March 2020 at 14:04:53 UTC, TodNaz wrote:
Hello!
class A
{
...
}
class B : A
{
...
}
class C : A
{
...
}
A example1;
B example2 = new B(...);
A = example2;
auto heir = A.whoheir(); ///
The question in this code is: is it possible to track the class
inheritor? Or is it beyond D?
Sorry if the question is fool ...
It is not generally known who has inherited a class from the
parents perspective.
Find the heir.
Hello!
class A
{
...
}
class B : A
{
...
}
class C : A
{
...
}
A example1;
B example2 = new B(...);
A = example2;
auto heir = A.whoheir(); ///
The question in this code is: is it possible to track the class
inheritor? Or is it beyond D?
Sorry if the question is fool ...
Re: Wired question related with Chinese characters
import std.stdio;
void main()
{
version( Windows ) {
//直接运行中文显示乱码,原因在于Windows控制台默认编码为 936，而D语言输出utf-8
//可以将控制台编码修改为 utf-8,命令为 "CHCP 65001"
//修改后就可以显示中文了
import core.sys.windows.windows;
SetConsoleCP(65001);
SetConsoleOutputCP( 65001 );
}
writeln("Hello World! 你好，中国！");
}
Re: Wired question related with Chinese characters
On Sunday, 22 March 2020 at 15:19:13 UTC, walker wrote:
I am new to dlang, I like it :)
I am on windows10 and use the terminal preview to test and run
programs.
In order to print Chinese characters correctly, I always use
void main()
{
string var1 = "你好"； # to!string(in_other_conditions)
writeln(var1);
}
I tried dstring but not working. Need Help Here.
-
The wired thing is the above approach may not work sometimes ->
corrupted characters show up.
However, if I run in the same place a little program written in
nim (just print hello world), then I run the same dlang
program, the Chinese character is print correctly.
Why that happened?
