Subject: Re: missing #include ?
To: None <tech-userlevel@NetBSD.org>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
Date: 12/12/2006 05:22:38
> The situation we're talking about is: foo.h needs sys/types.h to work
> properly, and if foo.h should include sys/types.h, or if the
> application pulls it in. Where is the performance difference?
When there's also bar.h which needs (and putatively includes)
sys/types.h. The .c-includes paradigm reads sys/types.h only once; the
.h-includes paradigm reads sys/types.h once per file that uses it.
Except that, as has been pointed out multiple times by now, gcc
optimizes this away if sys/types.h is protected with the canonical
ifdef/define/endif bracket. There still will be a performance hit, but
I fully expect that it will be too small to matter, quite possibly too
small to measure. (Anyone care enough to bother finding out?)
/~\ The ASCII der Mouse
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