enum vs const int

[Sean Kelly]

Lucas Goss wrote:
> I'm working on X headers and I have a file with a lot of this:
> 
> #define XK_BackSpace 0xff08
> #define XK_Tab       0xff09
> #define XK_Linefeed  0xff0a
> ...
> 
> Well with the recent mention of size of D programs on this newsgroup, I 
> decided to do a little test. I converted around 500 - 600 lines of code 
> (all #define like above with some comments in between), to const uint, 
> checked size, then converted those lines to using enums and checked 
> size. The documentation says that enums define constants in a manner 
> equivalent to: const int A = 0; ... So I was kinda surprised to find that:
> 
> #define->const uint = 246.5K
> #define->enum       = 233.1K
> 
> So... It's better to use enum's? Is this by design? And if the whole 
> file is just #define's like above, should it just be one big enum? Or 
> multiple enum's?

For header conversion, I agree with Don's suggestion that #defines 
should be converted to auto declarations.  ie.

const auto XK_BackSpace = 0xff08;
const auto XK_Tab       = 0xff09;
const auto XK_Linefeed  = 0xff0a;

I think this has the benefit of being more maintainable and more in line 
with the original semantics.  The executable size issue is a bit odd 
though.  Perhaps the optimizer deals better with enums than with const 
variables?


Sean