Multiple functions in a single DLL

[aleksandar Nedi]

I need to make dll file for computing user defined function in Lindo Lingo. I need to implement two new functions, but I can make only one myuser.dll file for use in Lingo.
But, talking with people from Lindo, it is possible to make two argument myuser.dll function, with first first argument as a "branching" variable. for example, For example,
@USER( 1, 2.4)
might compute the sin of 2.4, while
@USER( 2, 2.4)
would compute the cosine of 2.4. The first argument of 1 implies return the sin, while a first argument of 2 implies return the cosine.

My question is how to do that, because I am new to Vc++.
Thanks in advance,
Aleksandar

[weaknessforcats]

I would not do a branching argument.

What you do is create a VC++ project to create your DLL.

This project will produce your DLL plus a .LIB.

Next create a second VC++ project for your application.

Now comes the fun.

If you want to call your DLL functions as though they were C functions, then set the project properties of your application to include the name of the .LIB in your DLL project. PLus add the path to the LIB so your linker can find it.

Next, you ave to turn the C++ name mangler OFF for the functions in your DLL that will be called from your application. Make these extern "C" in the DLL project. That;s becuase te functions will be called by name as a string argument in GetProcAddress so that name better the same as the function inisde he DLL.

What the .LIB does is contain a phony function of the same name and arguments as the the function in the DLL. This phny functions calls LoadLibrary to load your DLL plus a call to GetProcAddress using the function name.

If you want to call LoadLibrary yourself followed by GetProcAddress then you do not need to add the .LIB to your application project.

Lastly, consider getting a copy of Windows via C/C++ by Jeffrey Richter where this is explained in great detail.