How to link a static lib if your application (MFC) uses runtime DLLs?

Category: visual studio vc


Juan Dent on Fri, 28 Jul 2017 19:31:58


I have the source for a static lib but for some reason it does not allowed configuring as dynamic lib (DLL). My app is an MFC with runtime multi-threaded DLLs and so linking throws a lot of errors.

What can I do to make this static lib work with my MFC app?

The REAL issue here is that some libraries cannot be built dynamically, so how can I use them in a user interface MFC app? Here the library in question is crytopp which I installed with vcpkg.exe and it says it cannot be built DLL...



Juan Dent


RLWA32 on Fri, 28 Jul 2017 20:16:35

If you wanted to use a DLL the general approach would be to create a wrapper DLL for the static library.

Juan Dent on Fri, 28 Jul 2017 20:19:42

But how? How could one create a DLL that links statically to the cryptopp library? Won't I get all the errors? What do you mean "wrapper DLL"? Could you please explain a bit?


Juan Dent

Juan Dent

RLWA32 on Fri, 28 Jul 2017 20:23:54

The wrapper DLL would link with the static library and export functions that would be forwarded to the corresponding functions in the static library.  For example,

__declspec(dllexport) int DLL_Func()


        return StaticLib_Func()


Juan Dent on Fri, 28 Jul 2017 20:27:35

But the wrapper DLL would use DLL runtime library so the same issue would occur as when I try to use the cryptopp library from the MFC app? I get what you say about the wrapper - that's great... But how will I link the DLL to the static library and then have MFC app link to this DLL? Won't runtime libraries conflict again?


Juan Dent

RLWA32 on Fri, 28 Jul 2017 20:32:08

I have no idea what the runtime library requirements are for the cryptopp static lib.  Does it require the static CRT?  As far as I know there is no general requirement that a static library must link to the static CRT. 

RLWA32 on Fri, 28 Jul 2017 20:34:02

I suppose problems could arise depending on usage and what gets passed across DLL/CRT boundaries.  That's an implementation detail that I can't address.

Juan Dent on Fri, 28 Jul 2017 20:34:55

when I try compiling I get:

1>cryptlib.lib(cryptlib.obj) : error LNK2038: mismatch detected for 'RuntimeLibrary': value 'MTd_StaticDebug' doesn't match value 'MDd_DynamicDebug' in RSAEncryptor.obj

RLWA32 on Fri, 28 Jul 2017 20:52:39

Can you build the static cryptopp library to use the CRT DLLs?

Juan Dent on Fri, 28 Jul 2017 21:06:20

Thanks for the suggestion --- actually I have to leave and can't do it, but will get back at you.

Thanks for your suggestions!!



Baron Bi on Thu, 03 Aug 2017 10:52:29

Hi Juan Dent,

thanks for posting here.

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Sera Yu