Yes, good point. I _thought_ there was a good example of why to use
the while false pattern but it's so far back in time that I can't
recall it. The only thing that I can find is
<http://c-faq.com/cpp/multistmt.html> which really doesn't apply in
this example.
Ah well, I know I've been burned by this but it may have just been a
by product of using it for a different kind of macro under a different
compiler.
Cheers,
-H.
On 24/04/2008, Ken Thomases <[EMAIL PROTECTED]> wrote:
> The do-while-false pattern is only necessary if you've got multiple
> statements or are otherwise surrounding the statements with braces.
>
> On Apr 24, 2008, at 5:43 PM, Herb Petschauer wrote:
>
> > What happens in a release build in this situation?
> >
> > if ( TRUE == someCondition )
> > DBOut( @"someCondition happened" );
> >
>
> The above is fine. It expands to:
>
> if ( TRUE == someCondition )
> ;
>
> Note the semicolon. It's an empty statement and serves as the body of the
> 'if'. The following statement would not be sucked up to become part of the
> 'if'.
>
>
> >
> > [foo someMethod];
> >
> >
> > I'd recommend the
> >
> > #define DBOut(fmt, ...)\
> > do\
> > {\
> > fprintf(etc);\
> > }\
> > while ( false )
> >
> > pattern lest you get different results in DEBUG vs non DEBUG code (no
> > reason to space the #define out like I've done if you don't want to).
> >
>
> The above probably doesn't hurt, but it's overkill. (On some compilers,
> which are probably not relevant, do-while-false is not well optimized. Or
> so I've read.)
>
> Cheers,
> Ken
>
_______________________________________________
Cocoa-dev mailing list ([email protected])
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com
This email sent to [EMAIL PROTECTED]
