GLFW3 and GLFW_INCLUDE_GLCOREARB - c++

Question

I'm using Visual Studio 2013, and as I am learning OpenGL 3.3 I thought best to use
#define GLFW_INCLUDE_GLCOREARB
#include <GLFW/glfw3.h>
to force 'intellisense' to not even show old depreciated functions such as glVertex2f etc...
However the inclusion of said #define prevents any gl* functions from showing up. Even glViewport is undefined. When attempting to compile a simple application I get among many errors
error C3861: 'glViewport': identifier not found
glcorearb.h is my include files path though, downloaded from http://www.opengl.org/registry/api/GL/glcorearb.h only yesterday.
I might be doing something completely wrong here. But here is my full source code...
// Include standard headers
#include <stdio.h>
#include <stdlib.h>
#define GLFW_INCLUDE_GLCOREARB
// Include GLFW3
#include <GLFW/glfw3.h>
//Error Callback - Outputs to STDERR
static void error_callback(int error, const char* description)
{
fputs(description, stderr);
}
//Key Press Callback
static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
glfwSetWindowShouldClose(window, GL_TRUE);
}
int main(){
GLFWwindow* window;
glfwSetErrorCallback(error_callback);
// Initialise GLFW
if (!glfwInit())
{
fputs("Failed to initialize GLFW\n", stderr);
exit(EXIT_FAILURE);
}
glfwWindowHint(GLFW_SAMPLES, 2); // 2x antialiasing
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); // We want OpenGL 3.3
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); //We don't want the old OpenGL
// Open a window and create its OpenGL context
window = glfwCreateWindow(640, 480, "Test", NULL, NULL);
if (!window)
{
glfwTerminate();
exit(EXIT_FAILURE);
}
glfwMakeContextCurrent(window);
glfwSetKeyCallback(window, key_callback);
while (!glfwWindowShouldClose(window))
{
float ratio;
int width, height;
glfwGetFramebufferSize(window, &width, &height);
ratio = width / (float)height;
glViewport(0, 0, width, height);
glClearColor(0.5f, 0.7f, 1.0f, 0.0f);
glClear(GL_COLOR_BUFFER_BIT);
glfwSwapBuffers(window);
glfwPollEvents();
}
glfwDestroyWindow(window);
glfwTerminate();
exit(EXIT_SUCCESS);
}