Log Error Once Macro

I thought of this earlier when I realized certain of the draw calls will fail silently, and I finally decided to actually write the code to do it. And it turned out a lot simpler than I expected, which is nice.

#define URHO3D_LOGERROR_ONCE(message) do {static bool once = true; if (once) {once = false; URHO3D_LOGERROR(message);} } while (false)

How it works:

  • Creates a unique static variable that will be initialized only once per variable for a given function (potentially per thread or something like that – I don’t remember the exact rules, and I’m not concerned in this case. LOG_FEW is still good enough versus LOG_PER_FRAME).
  • This single initialization is used to carry out the body of the if (the actual logging) only once.
  • The entirety is wrapped in a do {...} while(false) so that the macro still requires a semicolon after it like the other LOG macros.