OpenGL Programming Guide: The Official Guide to Learning OpenGL, Version 4.3, Eighth Edition

Accessing New OpenGL Functions

OpenGL changes all the time. The manufacturers of OpenGL graphics hardware add new extensions and the OpenGL Architecture Review Board approves those extensions and merges them into the core of OpenGL. Since each manufacturer needs to be able to update its version of OpenGL, the header files (like glcorearb.h¹), and the library you use to compile (like opengl32.lib, on Microsoft Windows, for example) may be out of sync with the latest version. This would likely cause errors when compiling (or more specifically, linking) your application.

To help you work around this problem, a mechanism for accessing the new functions was added for many of the window system libraries. This method varies among the different window ...