Removing external dependencies to MFC DLL project

Question

Im developing a MFC DLL project in VS2008. The dll compiles OK and I can call it fine from an GUI exe that a contractor has developed for me. Visual C++ Redistributables are required to be installed for my dll (and maybe the exe which is developed in C++ too)

Another company wants to licence my dll to use with their C++ exe. They have requested that my dll have no external dependencies. Is it possible to compile my dll to remove all external dependencies like the Visual C++ Redistributables?

Does setting /MT do this? I have read http://stackoverflow.com/questions/757418/should-i-compile-with-md-or-mt which makes some sense but I am concerned about dll hell.

Can this create issues with exe calling my dll? I read somewhere about that the exe and dll need to be using the same Visual C++ Redistributables or something.

I am somewhat new to C++. Any advice appreciated.

Answer 1

I'm not 100% sure, but I'm willing to bet that MFC won't work without the Visual C++ Redistributable and since your DLL is based on MFC, you don't have much of a choice. Maybe what they meant was that they don't want your DLL to use anything other than the regular Visual C++ stuff.

Answer 2

You can link with the static version of the CRT (yes, /MT) but it is quite dangerous. You'll have to carefully review your exports. Make very sure that none of them return C++ objects, not even an std::string (or CString). Or any pointers that the client code has to release. This will go wrong badly because the client will have its own CRT copy and use a different heap. That will leak the returned object/pointer, crash the program on Vista and Win7 when their secure heap manager detects that the pointer doesn't belong to the heap.

It might be a matter of debate what exactly an 'external dependency' means. Having a dependency on the CRT is not exactly external. You will however have to supply them with a version of the DLL that was built on the same version of Visual Studio that they use. The CRT can only be shared if the version matches.

Answer 3

Why not you package all the dependent dlls into a installer package and release to your customer?

I have seen some of the software package does include the vc's dependent libraries....