Re: Request Assistance Calling D from C++: weird visibility issue inside struct and namespace
On Wednesday, 8 November 2017 at 08:42:01 UTC, Petar Kirov [ZombineDev] wrote: Walter has recently been working on improving the C++ mangling, so be sure to test the latest dmd nightly build and if that doesn't work be sure to file bug report(s). https://github.com/dlang/dmd/pull/7250 https://github.com/dlang/dmd/pull/7259 https://github.com/dlang/dmd/pull/7272 Done: https://issues.dlang.org/show_bug.cgi?id=17975
Re: Request Assistance Calling D from C++: weird visibility issue inside struct and namespace
On Wednesday, 8 November 2017 at 15:12:05 UTC, MGW wrote: The useful material. https://www.youtube.com/watch?v=HTgJaRRfLPk Useful indeed, thank you.
Re: Request Assistance Calling D from C++: weird visibility issue inside struct and namespace
On Wednesday, 8 November 2017 at 06:34:27 UTC, Andrew Edwards wrote: I'm having a little bit of problem calling D code from C++ and would appreciate some assistance. First, given the following C++ program wich compiles, links, and runs without any problem: The useful material. https://www.youtube.com/watch?v=HTgJaRRfLPk
Re: Request Assistance Calling D from C++: weird visibility issue inside struct and namespace
On Wednesday, 8 November 2017 at 07:55:02 UTC, Andrew Edwards
wrote:
On Wednesday, 8 November 2017 at 07:30:34 UTC, evilrat wrote:
On Wednesday, 8 November 2017 at 06:34:27 UTC, Andrew Edwards
just using fully qualified name didn't make it?
void call_cpp() {
::foo("do great things"); // calling global foo
return;
}
No, it did not.
Are you sure you put it in a namespace in C++ too?
Yes. That wasn't the issue
otherwise there might be some name mangling incompatibility
that probably worth filling a bug report
That's the one. Thanks to the hint form, Nicholas Wilson, I was
able to track it down and resolve it with a call to
pragma(mangle).
-Andrew
Walter has recently been working on improving the C++ mangling,
so be sure to test the latest dmd nightly build and if that
doesn't work be sure to file bug report(s).
https://github.com/dlang/dmd/pull/7250
https://github.com/dlang/dmd/pull/7259
https://github.com/dlang/dmd/pull/7272
Re: Request Assistance Calling D from C++: weird visibility issue inside struct and namespace
On Wednesday, 8 November 2017 at 07:30:34 UTC, evilrat wrote:
On Wednesday, 8 November 2017 at 06:34:27 UTC, Andrew Edwards
just using fully qualified name didn't make it?
void call_cpp() {
::foo("do great things"); // calling global foo
return;
}
No, it did not.
Are you sure you put it in a namespace in C++ too?
Yes. That wasn't the issue
otherwise there might be some name mangling incompatibility
that probably worth filling a bug report
That's the one. Thanks to the hint form, Nicholas Wilson, I was
able to track it down and resolve it with a call to
pragma(mangle).
-Andrew
Re: Request Assistance Calling D from C++: weird visibility issue inside struct and namespace
On Wednesday, 8 November 2017 at 07:06:39 UTC, Nicholas Wilson
wrote:
On Wednesday, 8 November 2017 at 06:34:27 UTC, Andrew Edwards
wrote:
I'm having a little bit of problem calling D code from C++ and
would appreciate some assistance. First, given the following
C++ program wich compiles, links, and runs without any problem:
Try using `nm` on the C++ object to find out what it thinks the
mangling should be.
Check that against the mangling DMD produces.
Tried it, and it works.
Solution:
nm dexample | grep foo -> returns the __C++__mangling
Use it to define the function as such:
pragma(mangle, "__C++__mangling")
extern (C++) void foo(const char* str) {
// doing great things;
}
Thank you so much.
-Andrew
Re: Request Assistance Calling D from C++: weird visibility issue inside struct and namespace
On Wednesday, 8 November 2017 at 06:34:27 UTC, Andrew Edwards
wrote:
Modify example.cpp to:
==
// example.cpp
#include "example.h"
namespace SomeApi {}
struct SomeStruct {}
void call_cpp() {
foo("do great things");
return;
}
==
Compile and link and you have D program calling, calling C++,
which in turn calls D.
My problem is that I've encountered an issue where this does
not work: when the function is being called from a namespace or
local scope in C++, the linker cannot find the definition. For
example:
just using fully qualified name didn't make it?
void call_cpp() {
::foo("do great things"); // calling global foo
return;
}
In a last-ditch effort, I placed all of these definitions into
dexample.d and, it compiled, but still filed to linking:
Are you sure you put it in a namespace in C++ too?
otherwise there might be some name mangling incompatibility that
probably worth filling a bug report
Re: Request Assistance Calling D from C++: weird visibility issue inside struct and namespace
On Wednesday, 8 November 2017 at 06:34:27 UTC, Andrew Edwards wrote: I'm having a little bit of problem calling D code from C++ and would appreciate some assistance. First, given the following C++ program wich compiles, links, and runs without any problem: Try using `nm` on the C++ object to find out what it thinks the mangling should be. Check that against the mangling DMD produces.
Request Assistance Calling D from C++: weird visibility issue inside struct and namespace
I'm having a little bit of problem calling D code from C++ and
would appreciate some assistance. First, given the following C++
program wich compiles, links, and runs without any problem:
==
// example.h
SOME_API void foo(const char* str);
// example.cpp
#include "example.h"
namespace SomeApi {}
struct SomeStruct {}
int main() {
foo("do great things");
return 0;
}
void foo(const char* str) {
// doing great things;
}
==
Modify example.cpp to:
==
// example.cpp
#include "example.h"
namespace SomeApi {}
struct SomeStruct {}
void call_cpp() {
foo("do great things");
return;
}
==
Then create example.d:
==
void main() {
call_cpp();
}
extern (C++) void foo(const char* str) {
// doing great things;
}
==
Compile and link and you have D program calling, calling C++,
which in turn calls D.
My problem is that I've encountered an issue where this does not
work: when the function is being called from a namespace or local
scope in C++, the linker cannot find the definition. For example:
void SomeApi::CallFromNamespace() {
foo("do great things");
}
or
void SomeStruct::CallFromStruct() {
foo("do great things");
}
In a last-ditch effort, I placed all of these definitions into
dexample.d and, it compiled, but still filed to linking:
extern (C) void foo(const char* str) {
// doing great things;
}
extern (C++) void foo(const char* str) {
// doing great things;
}
extern (C++, SOME_API) void foo(const char* str) {
// doing great things;
}
extern (D) void foo(const char* str) {
// doing great things;
}
extern void foo(const char* str) {
// doing great things;
}
void foo(const char* str) {
// doing great things;
}
===
Linker error returned:
===
Undefined symbols for architecture x86_64:
"foo()", referenced from:
SomeStruct::CallFromStruct() in example.o
SomeApi::CallFromNamespace() in example.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to
see invocation)
make: *** [dexample] Error 1
Using DMD v2.077.0 on macOS High Sierra
-Andrew
