Why do I get the error “error: unknown type name 'virtual'” when trying to compile this code?

Question

Code:

struct IRenderingEngine {
    virtual void Initialize(int width, int height) = 0;
    virtual void Render() const = 0;
    virtual void UpdateAnimation(flo         


        

Answer 1

This is just a stupid guess since I've never tried compiling something with the word virtual in a C compiler... but is there any chance that you were trying to compile this C++ code as C code? That's the only reason I can think of that a compiler wouldn't understand the keyword virtual.

Answer 2

I moved the #import "IRenderingEngine.hpp" line from the GLView.h file to the GLView.mm - this prevented it from being imported into the main.m and HelloArrowAppDelegate.m files when they were compiled - and restricted the import into the .mm file, that could handle the C++.

I also had to make a couple of other fixes for bugs I'd introduced when typing in the code - so apologies if that wasn't the only thing that needed to be done, but it might help those with similar problems!

Answer 3

Changing the name of file "AppDelegate.m" to "AppDelegate.mm". It's correct!

Answer 4

The header <stdlib.h> is not the right one to use in a C++ program. When I replaced it with the c++ version of C's stdio library <cstdlib> then your code compiled for me.

Answer 5

If you're using Xcode 4, try changing the name of file "AppDelegate.m" to "AppDelegate.mm". It works for me.

Answer 6

if you call C++ files ( even if you only import them ) you need to change the .m file that call's it to .mm