FreeGLUT linking Issues in Linux

Question

I am running Linux Mint 14.1 64-bit

I have installed the following libs:

mesa-common-dev, freeglut3-dev, libglew-dev

through the apt-get tool.

Here are my includes, located in my Main.h file:

#include <cmath>
#include <cstdlib>
#include <iostream>
#include <stdio.h>

#include <GL/glew.h>
#include <GL/glut.h>
#include <time.h> 

I checked that the libs installed correctly, they seem to be located in /usr/lib/x86_64-linux-gnu and the headers in /usr/include/GL

I proceed to compile my Main.C file with the following flags:

g++ -Wall -Wextra -Weffc++ -Winit-self -Wmissing-include-dirs -Wswitch-default -switch-enum -Wunused-parameter -Wstrict-overflow=5 -Wfloat-equal -Wshadow -Wc++0x-compat -Wconversion -Wsign-conversion -Wmissing-declarations -Wstrict-null-sentinel -Woverloaded-virtual -Wsign-promo -Werror -pedantic -Wcast-qual -fno-pretty-templates -fmessage-length=80 -fdiagnostics-show-option -g -std=c++0x -pipe -frepo -c  Main.C -o Main.o

Main.o is generated without any issues, then I try to create the binary:

g++  -I/usr/include -L/usr/lib/x86_64-linux-gnu -lGL -lglut -lGLU -lGLEW -lX11 -lm -lrt -lpng Main.o -o main

And receive the following errors:

Main.o: In function `init()':
/path/to/Main.C:12: undefined reference to `glClearColor'
Main.o: In function `initGLUT(int, char**)':
/path/to/Main.C: undefined reference to `glutInit'
/path/to/Main.C:21: undefined reference to `glutInitDisplayMode'
/path/to/Main.C:24: undefined reference to `glutInitWindowSize'
/path/to/Main.C:25: undefined reference to `glutCreateWindow'
/path/to/Main.C:28: undefined reference to `glutDisplayFunc'
/path/to/Main.C:31: undefined reference to `glutKeyboardFunc'
/path/to/Main.C:34: undefined reference to `glutMouseFunc'
/path/to/Main.C:37: undefined reference to `glutReshapeFunc'
/path/to/Main.C:40: undefined reference to `glutIdleFunc'
Main.o: In function `printFPS()':
/path/to/Main.C:96: undefined reference to `glutGet'
Main.o: In function `reshape(int, int)':
/path/to/Main.C:123: undefined reference to `glutPostRedisplay'
Main.o: In function `getTime()':
/path/to/Main.C:129: undefined reference to `glutGet'
Main.o: In function `idle()':
/path/to/Main.C:141: undefined reference to `glutPostRedisplay'
Main.o: In function `display()':
/path/to/Main.C:148: undefined reference to `glClearColor'
/path/to/Main.C:149: undefined reference to `glClear'
/path/to/Main.C:150: undefined reference to `glFlush'
/path/to/Main.C:151: undefined reference to `glutSwapBuffers'
Main.o: In function `main':
/path/to/Main.C:164: undefined reference to `glutMainLoop'

The program compiles and links on another Linux system though. what could I be missing?

Answer 1

You have to pass the libraries last (after the object file)

g++  -I/usr/include -L/usr/lib/x86_64-linux-gnu Main.o \
  -lGL -lglut -lGLU -lGLEW -lX11 -lm -lrt -lpng -o main

The reason behind this is, that the linker only links symbols, that are currently undefined. If you pass the libraries before the object files, then there aren't any undefined symbols to be linked and compilation/linking will therefore fail.

Answer 2

The libraries need to come after your object files:

g++ -I/usr/include -L/usr/lib/x86_64-linux-gnu Main.o -lGL -lglut -lGLU -lGLEW -lX11 -lm -lrt -lpng  -o main