From: Richard Henderson <rth@twiddle.net>
To: Markus Armbruster <armbru@redhat.com>, qemu-devel@nongnu.org
Cc: Peter Maydell <peter.maydell@linaro.org>,
Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] Our use of #include is undisciplined, and what to do about it
Date: Thu, 17 Mar 2016 12:40:21 -0700 [thread overview]
Message-ID: <56EB0825.6070303@twiddle.net> (raw)
In-Reply-To: <87wpp4m6n1.fsf@blackfin.pond.sub.org>
On 03/15/2016 02:29 AM, Markus Armbruster wrote:
> Headers can
> be read multiple times, which can only hurt compilation time. You need
> to make an effort to avoid cyclic dependencies and excessive inclusion.
I just want to point out that the preprocessor understands the
#ifndef FOO
#define FOO
...
#endif
idiom, where nothing but comments precedes the #ifndef in the file, and
likewise nothing succeeds the matching #endif. If FOO is still defined at the
next #include of the file, the preprocessor will skip the #include entirely.
So don't let this be a consideration in the argument.
r~
next prev parent reply other threads:[~2016-03-17 19:40 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-15 9:29 [Qemu-devel] Our use of #include is undisciplined, and what to do about it Markus Armbruster
2016-03-15 9:40 ` Paolo Bonzini
2016-03-15 12:19 ` Markus Armbruster
2016-03-15 14:51 ` Paolo Bonzini
2016-03-15 10:03 ` Peter Maydell
2016-03-15 12:28 ` Markus Armbruster
2016-03-15 12:56 ` Peter Maydell
2016-03-15 13:39 ` Stefan Hajnoczi
2016-03-15 13:51 ` Daniel P. Berrange
2016-03-15 13:56 ` Dr. David Alan Gilbert
2016-03-16 18:23 ` Stefan Hajnoczi
2016-03-16 18:27 ` Dr. David Alan Gilbert
2016-03-17 11:25 ` Stefan Hajnoczi
2016-03-17 16:29 ` Dr. David Alan Gilbert
2016-03-17 19:21 ` Paolo Bonzini
2016-03-17 19:43 ` Dr. David Alan Gilbert
2016-03-17 19:58 ` Paolo Bonzini
2016-03-17 20:14 ` Richard Henderson
2016-03-17 20:27 ` Peter Maydell
2016-03-17 20:29 ` Richard Henderson
2016-03-17 21:02 ` Paolo Bonzini
2016-03-17 20:59 ` Paolo Bonzini
2016-03-17 19:40 ` Richard Henderson [this message]
2019-05-27 13:12 ` Markus Armbruster
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