Using OpenGL

[Darren via Digitalmars-d-learn]

On Saturday, 3 September 2016 at 11:27:09 UTC, Mike Parker wrote:
> On Saturday, 3 September 2016 at 11:13:30 UTC, Lodovico 
> Giaretta wrote:
>> 
>> Ah! Well, providing error messages is always useful. Now I see 
>> your issue: your callback has D linkage, but OpenGL expects a 
>> function with C linkage. So you have to put `extern(C)` on 
>> your callback declaration.
>
> Well, it's GLFW, not OpenGL, but yes they do need to be extern 
> (C) and also nothrow, as that is how the callback types are 
> declared in Derrlict:
>
> ```
> extern(C) nothrow
> void key_callback(GLFWwindow* window, int key, int scancode, 
> int action, int mode) {
>     if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
>         glfwSetWindowShouldClose(window, GL_TRUE);
> }
> ```

Hey, it worked!  Thanks a lot, I know what to do in the future 
now.  Just need to figure out why this triangle isn't showing up 
and I should be well on my way.