title: How do I know which version of OpenGL I am using?
body: <p>I started writing programs, in C (for now) using GLFW and OpenGL. The question I have is that, how do I know which version of OpenGL my program will use? My laptop says that my video card has OpenGL 3.3. Typing "glxinfo | grep -i opengl" returns:</p>
  
  <pre><code>OpenGL vendor string: NVIDIA Corporation
  OpenGL renderer string: GeForce 9600M GT/PCI/SSE2
  OpenGL version string: 3.3.0 NVIDIA 285.05.09
  OpenGL shading language version string: 3.30 NVIDIA via Cg compiler
  OpenGL extensions:
  </code></pre>
  
  <p>So is OpenGL 3.3 automatically being used ?</p>