"undefined reference" to functions I have certainly included

[dupi]

I am writing a program in C that needs to use colored text (DOS-type, 16 colors). I decided to use the color functions in conio.h because it seemed easiest and had everything I needed, but the compiler reports undefined references to the functions at the lines they are used, but I did include conio.h at the beginning of the file and with proper notation. I am also sure that I spelled the function correctly and used the correct parameters.
What is the problem here?
Thanks

[sand_man]

conio.h is not a standard header file so the functions you may think are there probably aren't. An example being the Borland version of conio.h is different to the gcc version.

[dupi]

I did not know that, but coincidentally, the way I determined which header file to use and what parameters and specifics to use was by searching through the header files. If the header file does have the function in it, is there another possible problem I could fix?

[Raven Arkadon]

in header files you usually only find the DECLARATIONS of functions.
you must specify the LIBRARY that contains the DEFINITIONS of the funtions.

(declaration = function name and type, definition = actual code)
like:

void my_func(); // declaration

void my_func()
{ // definition

}

so there is probably some conio.lib or something.


edit:
also: unresolved references are detected in the LINKING phase (if you get to that phase it means that your code compiled just fine)
- that is when all DECLARED symbols are being resolved.
whenever there is a "unresolved reference" it means that something was declared but never defined.

[quzah]

Well it would actually help a bit if you said what compiler and OS you're using. Not all compilers and operating systems are created equal. Furthermore, there is no "standard C method" of displaying color, because not all devices have color. Or displays for that matter...


Quzah.

[dupi]

there is a conio.c with the definitions of the functions, and it is in the same folder as the header file.

sorry I forgot to mention the compiler and OS. I am using DevC++ 4 with MingW, and my OS is Win XP.

Since conio does not sound to be standard, is there a better way I should make colored text? Note: I am a "noob" so the reason i chose conio is because it looked very simple. After coming from BASIC and VB I have lots of small problems in C that I often cant resolve and I end up giving up on projects because of them, so I try to keep everything siple so I can focus on the inherent difficulties of the project. The program i am doing now is hopeful of becoming a chess AI engine, so I should have enough problems with that...

[cwr]

If you just want colored text in a terminal, then ANSI escape codes are likely the most portable. Whether these work on Windows, I've no idea.

http://en.wikipedia.org/wiki/ANSI_escape_code

[dwks]

See the FAQ.

[dwks]

If you just want colored text in a terminal, then ANSI escape codes are likely the most portable. Whether these work on Windows, I've no idea.

They only work if you have ANSI.SYS in your CONFIG.SYS or where ever it should be.

[adrianxw]

My Console Programming Tutorial starting there covers the Windows way of adding colour to a console window, and a whole load of other stuff.

It is written in C++ but if you replace the cout with printf, they should work, they did before I converted them to C++.

The API routines will be the same of course.

[trancedeejay]

hi
I also have problem with undefined reference. Program worked fine before, I added few lines and it worked ok, but then my colegue updated the Monta Vista Linux and now when I want to compile it writes me undefined reference, path and the names of the functions
What should I do?
Have a nice Day

Matt

[trancedeejay]

I sorted out, what an idiot thing from me.
Have a nice Day

Matt