From: Michal Marek <mmarek@suse.cz>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: linux-kbuild@vger.kernel.org
Subject: Re: include guard weirdness
Date: Fri, 11 Jul 2014 14:20:56 +0200 [thread overview]
Message-ID: <53BFD6A8.5080803@suse.cz> (raw)
In-Reply-To: <87a98gnmeg.fsf@rasmusvillemoes.dk>
On 2014-07-11 13:51, Rasmus Villemoes wrote:
> Hi,
>
> gcc/cpp claims to be smart enough to recognize the include guard idiom,
> and most of the time this works very well: the second and subsequent
> #includes do not even cause the file to be opened (thus saving at least
> open+fstat+read+close). Except in a few cases, which are so common that
> it might be worth investigating.
>
> For example, linux/mm.h often shows up exactly twice in strace output;
> another very common header such as linux/types.h always occurs only
> once.
My guess is that <linux/mm.h> includes a header which at some point
includes <linux/mm.h> again.
Michal
next prev parent reply other threads:[~2014-07-11 12:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-11 11:51 include guard weirdness Rasmus Villemoes
2014-07-11 12:20 ` Michal Marek [this message]
2014-07-12 11:11 ` Rasmus Villemoes
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=53BFD6A8.5080803@suse.cz \
--to=mmarek@suse.cz \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux@rasmusvillemoes.dk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox