Using a DLL that links to a static lib

Question

I'm trying to build a solution in Visual C++ where I have a front-end project that references a DLL project that I created. In the DLL project I link to a static library (that I have not written) that has static objects and definitions. Everything builds fine but I have linking problems.

I have a couple of questions. First, I should only get unresolved symbols for objects that I reference in the front-end that are not exported, right? I want the DLL to be the only interface to the static library and do not directly reference any part of it in the front-end, and yet I get a number of unresolved symbols from this library. There symbols seem to be #included and at least some not directly linked by the DLL project. I suspect it has to do with the static declarations in the static lib but how can I deal with these?

Some of the unresolved symbol errors:

2>AnalysisVis.obj : error LNK2001: unresolved external symbol "public: __thiscall SharkException::SharkException(char const *,int,char const *)" (??0SharkException@@$$FQAE@PBDH0@Z)
2>AnalysisVis.obj : error LNK2001: unresolved external symbol "public: static class Bernoulli Rng::coinToss" (?coinToss@Rng@@2VBernoulli@@A)
2>AnalysisVis.obj : error LNK2001: unresolved external symbol "public: virtual bool __thiscall ChromosomeT<bool>::operator<(class Chromosome const &)const " (??M?$ChromosomeT@_N@@$$FUBE_NABVChromosome@@@Z)

What's the point in using a DLL as an interface to a static library? Please explain! — TonyK
The DLL isn't just an interface to the static library, it has its own functionality but it makes use of the static library. — Nigel
possible duplicate of static variable initialisation code never gets called — Martin York

hillel hillel · Accepted Answer · 2010-12-06T20:25:15

The exported symbols are mangled. If the static lib was compiled using a different compiler (or compiler version) than the one you are using, it is possible that the symbols your application is expecting to see were defined in the static lib using a different name mangling scheme. You can use the following command to get the name mangling used in the static lib and then compare it to the one in the error message:

>pushd <path_to_msvc_dir>\Microsoft Visual Studio X.0\VC\bin
>dumpbin /all [static_lib_path] > out.txt
>type out.txt | find /I "SharkException"
>type out.txt | find /I "coinToss"
>type out.txt | find /I "ChromosomeT"

BTW, does the DLL that uses the static lib compiles cleanly with the same compiler your application/solution does?

Using a DLL that links to a static lib

1 Answers