unresolved external symbol in C++ managed

Question

I have C++ managed dll compiled with /clr that has some global functions.

for example

void Managed2UnManaged(DataStructures::AAA^ elem, DataStructures::CPP::AAA* copy_elem);

when I try to use these functions in a C++ managed console application I get the following errors

error LNK2028: unresolved token (0A00048C) "void __clrcall Managed2UnManaged(class DataStructures::AAA ^,class DataStructures::CPP::AAA *)" (?Managed2UnManaged@@$$FYMXP$AAVAAA@DataStructures@NextIn@@PAV1CPP@23@@Z)

error LNK2019: unresolved external symbol "void __clrcall Managed2UnManaged(class DataStructures::AAA ^,class DataStructures::CPP::AAA *)" (?Managed2UnManaged@@$$FYMXP$AAVAAA@DataStructures@NextIn@@PAV1CPP@23@@Z)

I added to the console application a reference to the dll but it still gives the error.

I also tried adding __declspec(dllexport) but then I get

error C3395: 'Managed2UnManaged' : __declspec(dllexport) cannot be applied to a function with the __clrcall calling convention

and if I specify __stdcall I get

error C4439: 'Managed2UnManaged' : function definition with a managed type in the signature must have a __clrcall calling convention

I am using VS2012.

the h file has

class XXX {
 public:
static void Managed2UnManaged(DataStructures::RegResult^ elem,     DataStructures::CPP::RegResult* copy_elem);
};

and the cpp file

 void XXX::Managed2UnManaged(DataStructures::RegResult^ elem, DataStructures::CPP::RegResult* copy_elem)
{

}

Problem Solved. the problem was that I also needed to declare the class public ref. this caused a different problem because that the native c++ types are private. so I had to use the make_public pragma. Thanks all.

did this function exported by the DLL? if it is, please check the calling conventions are the same, the error message indicates the calling convention is clrcall. — Matt
I tried exporting by adding __declspec(dllexport) but then I get error C3395: 'Managed2UnManaged' : __declspec(dllexport) cannot be applied to a function with the __clrcall calling convention — gerstla
_clrcall is not compatible with dllexport. Is your console application a native application, you may change it to a managed one. — Matt
You only posted the declaration of the function. Where is the code for the function actually located? — Hans Passant

rodrigo rodrigo · Accepted Answer · 2012-12-18T08:45:16

I think that the problem may be that the CLR doesn't allow global functions.

You must create a managed class and write your function as a static member function of that class, for that function to be exported.

unresolved external symbol in C++ managed

1 Answers