Function glfwSetWindowFocusCallback
Prototype
extern(C) extern glfwSetWindowFocusCallback( GLFWwindow* window, extern(C) nothrow void function(GLFWwindow*, int) cbfun ) nothrow nothrow;
extern(C) extern glfwSetWindowFocusCallback( GLFWwindow* window, extern(C) nothrow void function(GLFWwindow*, int) cbfun ) nothrow nothrow;