C++ _inline is being ignored in a singleton and showing up in my profiler. How come?

Question

I have a lot of classes in my project accessed by a singleton like so:

_inline GUI_BS_Map* GUI_GetBS_Map()
{
    static GUI_BS_Map obj;
    return &obj;
};

As I understand it, this code should be inlined. I have the Visual Studio (2005) options set to inline anything suitable, and my profiler (AQTime) is definitely not set to override the _inlines. However, when I profile the code, there they are, thousands of calls to each of my singleton functions. What could I be missing? (I'm profiling a debug build (to get symbols for the profiler) but with all of the speed optimisations turned on.) Any suggestions much appreciated!

Answer 1

The compiler is free to ignore inline and _inline. In Visual C++ you can try __forceinline that makes the compiler inline functions unless there're serious reasons not to do so (such reasons are listed in the linked MSDN article).

Answer 2

Inline is only a suggestion to the compiler. It may ignore your suggestion or even inline functions that you haven't marked to inline.

I would suggest trying to move the local static outside of your function, recompile, and debug again to check to see if you see a change in behavior. It seems that trying to inline this function with a local static would be an issue.