Heyas,

I was trying to compile the source code from NeHe's seconds OpenGL Lesson. When I try to compile the source using the included make file, I get the following error:

$ make
gcc -Wall -ansi lesson02.c -o lesson02 -lGL -lGLU `sdl-config --cflags --libs`
/usr/lib/gcc-lib/i486-slackware-linux/3.3.4/../../../../i486-slackware-linux/bin/ld: cannot find -lGLU
collect2: ld returned 1 exit status
make: *** [all] Error 1

When I try to compile the same source file without the -lGLU tag, I get the following error:
$ gcc lesson02.c -o lesson02 -lSDL -lSDLmain -lGL
/tmp/ccQNySIB.o(.text+0x8a): In function `resizeWindow':
: undefined reference to `gluPerspective'
collect2: ld returned 1 exit status

If I go in and comment this line out, everything compiles, however the program does nothing. It is just a blank screen. So, I've narrowed down the problem and I think it is because the gluPerspective requires the -lGLU flag, but it will not work. I am running Slackware 10.0 and my gcc is version 3.3.4. Is there a package I do not have that I need to install to get the -GLU flag to work so I can compile these sample programs?

Thanks,
Chris

I just managed to get this to work. For anyone else who might be having a problem like this, my libGLU files were in /usr/X11R6/lib/ and not /usr/lib/ and aparently gcc looks for the files in /usr/lib/ unless told otherwise. So I just copied them from /usr/X11R6/lib/ to /usr/lib and now the -lGLU flag works with gcc and the lessons compile without a problem.

-Chris-

Congrats on figuring out your own problem, but your solution is not quite the best...

When you copy libraries from their proper location to another, you set yourself up for problems later on. Your package manager (or make install if you compile from source) is going to replace the /usr/X11R6 files, but it's not going to know about the files in /usr/lib, yet these files will be used when you compile your program (so if you upgrade to fix a problem and forget to recopy those files, you won't see the problem go away!).

You could get around this by providing symlinks to the files, but the best way is to use gcc's -L switch. -L /usr/X11R6/lib would tell the system to search in that directory (as well as the defaults) for libraries when building the program.