Loading Vertex Shader Error - opengl

Question

I am attempting to learn OpenGL 2.0 and I am trying to draw a triangle onto the screen.
When I try to load the vertex shader, it won't compile Here is my code(I am aware that my code is incomplete, I am just running it periodically to make sure I don't get too deep with errors):
#include <iostream>
#include <stdlib.h>
#include <GL/glew.h>
#include <GLUT/glut.h>
int init_resoureces(void){
GLint compile_ok = GL_FALSE, link_ok = GL_FALSE;
GLuint vs = glCreateShader(GL_VERTEX_SHADER);
const char *vs_source =
"#version 120\n"
"attribute vec2 coord2d;"
"void main(void) {"
"gl_position = vec4(coord2d, 0.0, 1.0);"
"}";
glShaderSource(vs, 1, &vs_source, NULL);
glCompileShader(vs);
glGetShaderiv(vs, GL_COMPILE_STATUS, &compile_ok);
if (0 == compile_ok){
fprintf(stderr, "Error in the vertex shader\n");
return 0;
}
return 1;
}
void onDisplay(){
//fill in later
}
void free_resources(){
}
GLfloat triangle_vertices[] = {
0.0, 0.8,
-0.8, -0.8,
0.8, -0.8
};
int main(int argc, char * argv[])
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH);
glutInitWindowSize(640, 480);
glutCreateWindow("My First Triangle");
GLenum glew_status = glewInit();
if (glew_status != GLEW_OK){
fprintf(stderr, "Error: %s\n", glewGetErrorString(glew_status));
return EXIT_FAILURE;
}
if (1 == init_resoureces()) {
glutDisplayFunc(onDisplay);
glutMainLoop();
}
free_resources();
return EXIT_SUCCESS;
}
The program quits and says there is an error in the vertex shader (as it should with the if statement detecting compiling errors). I can't find the error in my shader, though.
Does someone know what I'm doing incorrectly?
If it matters, I am using Xcode and OS X 10.8
Thanks!

Answer 1

The OpenGL Shader Language, GLSL, is case-sensitive.
Make sure you capitalize gl_Position correctly.