minwin

[Walter Bright]

Gregor Richards wrote:
>>     version (NOTWINDOWS) => version (LINUX)
> I hate to say this, but that example just plain stupid. All it will ever 
> do is limit your code to work on only certain operating systems. That's 
> hindering portability, and that's no good.
> 
> As it turns out, it's often the case that such-and-such does work on 
> every sane operating system, and therefore version (!Windows) makes sense.

I've seen a lot of code that did that, and it was nearly always broken. 
That's one motivation for operating system versions should be positives, 
not "this is for not windows" or "this is for not linux". Such 
fundamentally are wrong, and will bite you or the maintainer sooner or 
later.

> I know I've ran into instances where $WEIRD_SOCKET_FEATURE_X crashes 
> horribly on a certain operating system, so I was forced to #ifndef 
> __APPLE__. The same feature worked fine on literally every other system 
> I tested it on, so it would be ridiculous to do an #ifdef for everything 
> BUT Apple.
> 
> version (darwin)
> version (BSD)
> version (Solaris)
> version (SkyOS)
> version (DJGPP)
> version (HURD)
> version (ObscureOS)
> version (OSYetToBeInvented)

What I'd do is have APPLE_SOCKET_BUG with the workaround, and the 
default for the else. That way, you can search for the workarounds for 
that bug, and they won't be confused with other apple features or other 
apple bugs. Furthermore, if apple fixes that bug, you can update your 
code much easier with a targeted update than if you painted the entire 
apple os that way.

It's common practice (such as in STL) to target specific bugs with 
specific identifiers, and then have a configuration file which sets up 
the bugs for each system.

> Thinking in positives is great, but so unrealistic as to be completely 
> valueless. version statements in reality are used like indexes into 
> sets. The set of operating systems, the set of C libraries, the set of 
> compielrs. And it's unrealistic and ignorant to try to index EVERY 
> member except for whichever one you like, especially since the list is 
> always growing.
> 
> Not everything has a positive opposite. In fact, most everything doesn't.

I don't agree, and as an example I suggest the socket bug approach above.