I'm fairly new to C++, and I'm writing a program at Uni for a project. I need to include a library from the Vienna RNA package www.tbi.univie.ac.at to use one of the functions in it.

I am using both linux (g++ compiler) and Windoze (Borland / DevC++), so a solution for either would suit me.

I have tried putting

#include "fold.h"

in my program (the header file that contains the function i want to use - the fold(char *, char *) function), and adding the c source file for that header to my Borland project, but when i try and use the function I get an 'unresolved external' error on compiling.

I figure it's something to do with object files, but I don't really get what these are - are they different under linux and win? (they have different file extensions, .o and .obj)?

when i use g++ under linux i get a similar error message.

could someone pleeeeeeeease tell me what to do, coz i know this is something that should be really easy to accomplish, and it's really annoying me coz all i need is one number from one goddamn function!!!!!!!!

just a run-thru of how to include external libraries, either for borland or for linux would be exceptionally useful, or even a link to an appropriate tutorial on the net.

Cheers

Will

I don't like combining 2 different compilers, I suggest you try to avoid it if possible. Object files *should* be the same no matter which compiler, but there may be differences between the .o file (fron gcc) and .obj (from borland), which the opposing compiler won't like.

Choose one compiler & stick to it.

Now. Object files are partially compiled source, files with no main function, just other functions. You've to explicitly tell the g++ compiler to include the .o file when compiling your main program, like so:

Then the compiler knows where these functions are available, and can include them.

Hope this helps
GF