I'll be honest... loading GL function pointers is a real pain.
For one, you should generally use the layer for the Windowing System to grab function pointers. This solves various potential problems (none of which would currently happen on any system except for Windows). GLEW helps with this but it's actually a broken piece of software.
For one, GLXEW is garbage. I don't mean it sucks, I mean it's literally unusable.
http://sourceforge.net/p/glew/bugs/240/
It still does not fetch extension strings correctly... after 3 frickin' years man...
http://sourceforge.net/p/glew/bugs/174/?page=2
And there's also some confusions like the use of glewExperimental, which should *never* be used except it's used all the time. It breaks software constantly actually.
So, alternatives? glLoadGen, GLAD, or just load each function you need individually using something like SDL. glLoadGen doesn't work well for a few fundamental reasons... I actually wrote a bug report and made several patches... even maintained a fork for awhile. It's not fixable.
GLAD is better and uses python. Still ugly as dirt, doesn't actually parse the XML as cleanly as it should and the header generation is just chopping strings together which often creates bugs. It's usable but it could be better.
In other words, I don't like any function loader for OpenGL right now. The project I studied the various layers (GLX/WGL/CGL(and cocoa)) for uses GLAD... but we went from GLEW, to hand written, to glLoadGen, to GLAD. They all suck and after over a decade of loaders, they should really be better written.
/me going about his day ignoring that he's hypocritical for not writing that software himself.