undefined reference to `GlewInit' - OpenGL - c

Question

I get this error when trying to make the executable, the code compiles correctly and yet when I hit the make command I get this error message:
gcc -c helloworld.c
lewis#lewis-desktop ~/Desktop/Dev/gl $ make
gcc -o hello-gl helloworld.o -L/usr/X11R6/lib -lGL -lglut -lGLEW -lm
helloworld.o: In function `Initialize':
helloworld.c:(.text+0x55): undefined reference to `GlewInit'
collect2: ld returned 1 exit status
make: *** [helloworld] Error 1
I'm running Linux Mint 13 and I think it's something to do with my makefile, I don't know too much about them so I hacked one together and found some code online:
GL_INCLUDE = /usr/X11R6/include
GL_LIB = /usr/X11R6/lib
GL_GLEW = /user/include
helloworld: helloworld.o
gcc -o hello-gl $^ -L$(GL_LIB) -lGL -lglut -lGLEW -lm
.c.o:
gcc -c -o $# $< -I$(GL_INCLUDE)
clean:
rm -f hello-gl hello-gl-dummy hello-gl.o util.o hello-gl-dummy.o
My Code:
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <GL/glew.h>
#include <GL/freeglut.h>
#define WINDOW_TITLE_PREFIX "Hello, World!"
int CurrentWidth = 600,
CurrentHeight = 400,
WindowHandle = 0;
void Initialize(int, char*[]);
void InitWindow(int, char*[]);
void ResizeFunction(int, int);
void RenderFunction(void);
int main(int argc, char* argv[])
{
Initialize(argc, argv);
glutMainLoop();
exit(EXIT_SUCCESS);
return 0;
}
void Initialize(int argc, char* argv[])
{
GLenum GlewInitResult;
InitWindow(argc, argv);
GlewInitResult = GlewInit();
if (GLEW_OK != GlewInitResult) {
fprintf(stderr, "ERROR: %s\n", glewGetErrorString(GlewInitResult));
exit(EXIT_FAILURE);
}
fprintf(
stdout,
"INFO: OpenGL Version: %s\n",
glGetString(GL_VERSION)
);
glClearColor(0.2f, 1.0f, 0.8f, 0.3f);
}
void InitWindow(int argc, char* argv[])
{
glutInit(&argc, argv);
glutInitContextVersion(4, 0);
glutInitContextFlags(GLUT_FORWARD_COMPATIBLE);
glutInitContextProfile(GLUT_CORE_PROFILE);
glutSetOption(
GLUT_ACTION_ON_WINDOW_CLOSE,
GLUT_ACTION_GLUTMAINLOOP_RETURNS
);
glutInitWindowSize(CurrentWidth, CurrentHeight);
glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
char *states[] = {"Hello", "My", "Name", "Is", "Lewis"};
WindowHandle = glutCreateWindow(WINDOW_TITLE_PREFIX);
if(WindowHandle < 1) {
fprintf(
stderr,
"KERN_ERROR: Could not create a new rendering window.\n"
);
exit(EXIT_FAILURE);
}
glutReshapeFunc(ResizeFunction);
glutDisplayFunc(RenderFunction);
}
void ResizeFunction(int Width, int Height)
{
/*captures the resize data from the OS and assigns it to the global
variable CURRENT_WIDTH & CURRENT_HEIGHT */
CurrentWidth = Width;
CurrentHeight = Height;
glViewport(0, 0, CurrentWidth, CurrentHeight);
}
void RenderFunction(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
/*the next line takes the data from the back-buffer to the screen */
glutSwapBuffers();
glutPostRedisplay();
}

Answer 1

The names for the GLEW functions should start from 'glew', not 'Glew'.
So it is
GlewInitResult = glewInit();
C is case-sensitive and all the OpenGL-related libs usually start the names of the functions with lowercase letters.