OS X OpenGL Failure

[Jalfor]

SFML Works when I don't use OpenGL but when I do I get this error:

Undefined symbols for architecture x86_64:
  "_glClear", referenced from:
      _main in main.o
  "_glViewport", referenced from:
      _main in main.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

I am using the default template with XCode 4.6 (although I've switched off C++11 because that made it break) and I used the example code from the "A typical OpenGL-with-SFML program" here: http://sfml-dev.org/tutorials/2.0/window-opengl.php

Thanks for any help

[Laurent]

If you use OpenGL, you must link your app to the OpenGL framework/library.

[Jalfor]

That worked, Thanks.