C++ Passing std::string by reference to function in dll

Question

I have the problem with passing by reference std::string to function in dll.

This is function call:

CAFC AFCArchive;

std::string sSSS = std::string(         


        

Answer 1

C++ classes like std::string can be used across module boundaries, but doing so places significant constraints on the modules. Simply put, both modules must use the same instance of the runtime.

So, for instance, if you compile one module with VS2013, then you must do so for the other module. What's more, you must link to the dynamic runtime rather than statically linking the runtime. The latter results in distinct runtime instances in each module.

And it looks like you are exporting member functions. That also requires a common shared runtime. And you should use __declspec(dllexport) on the entire class rather than individual members.

If you control both modules, then it is easy enough to meet these requirements. If you wish to let other parties produce one or other of the modules, then you are imposing a significant constraint on those other parties. If that is a problem, then consider using more portable interop. For example, instead of std::string use const char*.

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Now, it's possible that you are already using a single shared instance of the dynamic runtime. In which case the error will be more prosaic. Perhaps the calling conventions do not match. Given the sparse level of detail in your question, it's hard to say anything with certainty.