如何将库静态链接到DLL？

Question

I'm in DLL hell. I have 2 DLLs let's say A.dll and B.dll which have a name collision - the same C++ class name is used in each, etc. Both DLLs are available as static libs.

Can I create a 'wrappe' DLL, say Aprime.dll which exports a similar class, methods, etc. as in A.dll, and delegates the functionality to the class in A.lib, but statically linked into the Aprime.dll? Wouldn't that avoid the name collision?

I've been trying this, but not sure I have the MSVS project set up correctly. Aprime.dll is being produced, but according to Dependency Walker Aprime.dll is still loading A.dll.

I've been searching, but most stuff I find applies only to statically linking in the CRT or MFC, which have their own switches.

I added A.lib under Linker -> Input -> Additional Dependencies.

Am I missing some magic linker command line switch or something?

Answer 1

Yes that method should work. The key though is to ensure that you do not include any of the original A.dll header files in the Aprime.dll header file. Otherwise if someone includes Aprime.h/pp then it will include Ah/pp and you will then have a clash again.

So you want something like:

Ah

// Library A includes
class test
{
};

Bh

// Library B includes
class test
{
}

Aprime.h

// Proxy class
class myTest
{
}

Aprime.cpp

#include "A.h"
#include "Aprime.h"

...

main.cpp

#include "Aprime.h"
#include "B.h"

...

Note that main never includes both A and B. In only includes Aprime and B. B is still static lib and Aprime is a DLL.

Answer 2

Yes, you can, and it's supported at a very low level by Windows. Aprime.DLL is effectively empty except for a bunch of references to A.DLL .