In OpenGL some functions take pointers and these are easily handled via v = Pointer.new('f', 20) glVertexPointer(3, GL_FLOAT, 3, v) (the C prototype is void glVertexPointer(GLint size, GLenum type, GLsizei stride, const GLvoid * pointer); however in some cases this function has been overloaded so you pass in an integer as the last parameter. In C this is easy glVertexPointer(3, GL_FLOAT, 3, (void *) 12) but how do I do this with MacRuby Pointer objects? (the source code and googling hasn't helped). I can (and have) written this as an objective-C method and called this method from ruby so I have a workaround. I can understand if this is not possible or desirable from ruby as it is a horrible bit of API design in OpenGL in any case. Dave.