explore derelict sources - https://github.com/aldacron/Derelict3/blob/master/import/derelict/glfw3/functions.d#L135 - here is ur function.
btw i'm not think glfw3 is stable enough, i has some unresolved externals even with glfw2 on windows(one example is glfwGetGLVersion) so i think it's more likely a glfw issue. glfw2 official site has D bindings(outdated) in their support.
concerning examples, yes with D it is always a good choice to start with examples provided by authors, D still rapidly grows and so on. also it is a good to start asking on dlang.org forum. and last note, dsource is quite outdated and most of development acivity migrated to github.
hope all this helps you.