• via Digitalmars-d-bugs (41/41) Jan 09 2017 https://issues.dlang.org/show_bug.cgi?id=17081

via Digitalmars-d-bugs <digitalmars-d-bugs puremagic.com> writes:

https://issues.dlang.org/show_bug.cgi?id=17081

          Issue ID: 17081
           Summary: Bodies in extern cpp functions in D files are not
                    linked
           Product: D
           Version: D2
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody puremagic.com
          Reporter: alexandru.razvan.c gmail.com

While trying to interface C++ with D I noticed the bodies for external c++
functions in D files are not linked. For example I have the following files:

// D Source
import core.stdcpp.typeinfo;
import core.stdc.string:strcmp;

extern (C++) void fun(type_info ti)
{
    assert(strcmp(ti.name(), "i") == 0);
}

// C++ Source
#include <typeinfo>

extern void fun(std::type_info *ti);

int main() {
    fun(&typeid(int));
}

When trying to compile and link the 2 objects I get the following error: "
undefined reference to `std::type_info::name() const'".

To solve this I edited druntime/src/core/stdcpp/typinfo.d and actually took the
GNU libcpp implementation and translated it.
Now instead of "final const(char)* name();" we actually have a full
implementation: 
final const(char)* name()() const nothrow {
                return _name[0] == '*' ? _name + 1 : _name;
}

Using this seems to solve the problem. I propose actually implementing all
non-virtual functions from druntime/src/core/stdcpp in order to solve this.

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