Re: Can I Exclude a DLL at runtime.

You cannot do this unless you load the DLL explicitly by using LoadLibrary (or
LoadLibraryEx). This requires that you use GetProcAddress to resolve the addresses.

So the key issue here is that if you have a method
    int SomeFunc(LPCTSTR p, UINT n);
then you have to do the following:

    typedef int (*SomeFunc_t)(LPCTSTR p, UINT n);
or, if you had
    int CALLBACK SomeFunc(LPCTSTR p, UINT n);
you have to write
    typedef int (CALLBACK * SomeFunc_t)(LPCTSTR p, UINT n);
and include a header file of these definitions instead of the .h file you are using.

Next, you have to declare a set of variables (often these are global variables), e.g.,
YOUR header file declares
    extern SomeFunc_t SomeFunc;
and in some module (I usually do a separate module to handle this)
    SomeFunc_t SomeFunc;

NOTE that I carefully choose the name of the function variable to be the same as the name
of the function as it was written.

NOW, what you do is

BOOL LoadHardwareDLL()
   {
    lib = ::LoadLibrary(ddllnamehere);
    if(lib == NULL)
        return FALSE;
    if(!ResolveAddresses(lib))
        {
         ::FreeLibrary(lib);
         return FALSE;
        }
    return TRUE;
   }

static BOOL ResolveAddresses(HINSTANCE lib)
   {
    SomeFunc = (SomeFunc_t)GetProcAddress("SomeFunc");
    if(SomeFunc == NULL)
        return FALSE;
    ...repeat for each entry point
    return TRUE;
   }

Now note that if your program is compiled with the regular .h file for the library, the
one you are currently using, you have calls of the form
    int value = SomeFunc(_T("String"), 17);
which resolve to import records that cause the DLL to be loaded implicitly. BUT, if you
use your special .h file, then you have to write
    int value = SomeFUnc(_T("String"), 17);
Whoops! IT'S THE SAME THING! YOUR SOURCE CODE DOES NOT CHANGE!

So you can write

#ifdef I_WANT_EXPLICIT_DLL_LOADING
#include "MyHeaderFile.h"
#else
#include "OriginalHeaderFile.h"
#endif

and your code would be

#ifdef I_WANT_EXPLICIT_DLL_LOADING
if(dash_h_switch_not_specified)
   {
    if(!LoadHardwareDLL())
         ... deal with failure; hardware not available
   }
else
   {
    ...hardware not available
   }
#else
    ...hardware is available
#endif

so now you can do it either way. (Obviously, the bodies of the LoadHardwareDLL and
ResolveAddresses can be excluded if I_WANT_EXPLICIT_DLL_LOADING is not defined)

So if -H is specified, you don't call LoadHardwareDLL(); if it is not specified, you do.

Remember to FreeLibrary when you are all done with the DLL, such as when your program is
terminating. It's just considered good practice to do so.

This is a sketch; you will have to know the actual export names and a bunch of other
details, but this is the basic structure