How to import external dll library to Borland C++ 6?

Question

I build an application in Borland C++ 6 and I'd like to import external, non Borland library (FFTW, to be exact, http://www.fftw.org).

I have downloaded the fftw dll file, used the implib.exe program to build a lib file known to Borland, included fftw.h in source and copied fftw.h to Borland/include, fftw.lib to Borland/lib and .h, .dll and .lib files to my project folder.

Unfortunately I get several linker errors, which claims:

Unresolved external '{name of the FFTW function}' referenced from {name of the source file}

What do I do wrong?

Some1 Some1 · Accepted Answer · 2012-08-22T19:10:13

I'm just telling from a similar story how I managed to get it to work...

There was a DLL that worked (was being sucessfully imported) with Delphi 7, VB.NET and Java. I wanted to make a program with Borland C++ Builder 6 with it. I had the function prototypes and the exact declarations that made the import on those languages. Reasonable?

I thought it would be easy, but I stucked on many dead ends without sucess, with step by step "blind" guides that didn't worked for me. And the IDE or command outputs not helping either.

After a few days I tried (from question 4599357, although the DLL isn't in Visual C++):

using "implib" without "-a" and
having the prototypes declared like this:

extern "C" __declspec(dllimport) __stdcall int someDll_someFunction(someTypes someArgs, ...);

Note that the normal function prototype is at the end. If you have the "normal" prototypes, just add "extern "C" __declspec(dllimport) __stdcall" before them to your source code or header file. :) And I only have functions that return "int", this is why I put "int" there.

How to import external dll library to Borland C++ 6?

3 Answers