Organization of DLL linked functions

Question

This is a code organization question.

I got my basic code working but when I expand it, it will be terrible. I have a DLL which I don't have a .lib for. Therefore I have to use the whole LoadLibrary()/GetProcAddress() combo. It works great. But this DLL that I'm referencing has 100+ functions. My current process is:

1) Typedef a type for the function. E.g.: typedef short(_stdcall *type1)(void);

2) Assign a function name that I want to use such as type1 function_1;

3) Load the DLL, then do something like: function_1 = (type1)GetProcAddress(hinstLib, "_mangled_funcName@5");

Normally I would like to do all of my function definitions in a header file but because I have to use the load library function, its not that easy. The code will be a mess. Right now I'm doing (1) and (2) in a header file and was considering making a function in another .cpp file to do the load library and dump all of the (3)'s in there. I considered using a namespace for the functions so I can use them in the main function and not have to pass over to the other function.

Any other tips on how to organize this code? My goals are to be able to use function_1 as a regular function in the main code. If I have to a ref::function_1 that would be okay but I would prefer to avoid it. This code for all practical purposes is just plain C at the moment.

Answer 1

You can try to generate .lib file from .dll: https://wiki.videolan.org/GenerateLibFromDll/

After that the task is much simpler and cleaner - to create a header with function declarations. This can be done manually or (semi-)automated.

Answer 2

Create a compact meta format (AKA a DSL) for describing the function signatures and write a code generator which reads that meta-format and produces all of the needed headers and cpp files for the loadLibrary code. So you don't have to bother with the readability of the C or C++ code too much, just make sure your meta-format is well readable.

Answer 3

A code generator script would be a very neat solution, you should investigate.

If you want to stick to C only, you could probably clean up the code a bit using a couple macros. Maybe one to declare the typedef and the variable in one go, similar to this:

#define FUNC_DECL(retType, name, param)\
     typedef retType (_stdcall * name##_f)(param);\
     name##_f name;

And one to initialize the variable in a cleaner way:

#define FUNC_LOAD(name, lib)\
     name = (name##_f)GetProcAddress(lib);

So you would now just need to add a FUNC_DECL(function_X) in the global scope of a C file and call FUNC_LOAD(function_X, lib) in some initialization function. You would still have to declare an extern statement in a header file however, if function_X is to be visible elsewhere. E.g.: extern function_X_f function_X;