By using the native access functions you assert that you know what you're doing and how to fix problems caused by using them. If you don't, you shouldn't be using them.
Before the inclusion of glfw3native.h, you must define exactly one window system API macro and exactly one context creation API macro. Failure to do this will cause a compile-time error.
The available window API macros are:
GLFW_EXPOSE_NATIVE_WIN32GLFW_EXPOSE_NATIVE_COCOAGLFW_EXPOSE_NATIVE_X11The available context API macros are:
GLFW_EXPOSE_NATIVE_WGLGLFW_EXPOSE_NATIVE_NSGLGLFW_EXPOSE_NATIVE_GLXGLFW_EXPOSE_NATIVE_EGLThese macros select which of the native access functions that are declared and which platform-specific headers to include. It is then up your (by definition platform-specific) code to handle which of these should be defined.