title: Undefined reference to
body: <p>I'm doing an opengl/qt3 assignment, but I'm running into an undefined reference error:</p>
  
  <pre><code>Renderer.h:
  ...
  #include "Mesh.h"
  ... Mesh mesh;
  
  Renderer.cpp: 
  ...
  mesh.load("ball.obj"); 
  ...
  
  Mesh.h:
  ...
  bool load(string filename);
  ...
  
  Mesh.cpp:
  #include "Mesh.h"
  ...
  bool Mesh::load(string filename) { ... }
  ...
  </code></pre>
  
  <p>but the compiler complains about the line mesh.load("ball.obj") as an undefined reference... What is going on? Thank you in advance!</p>