From: navych@126.com (Navy)
To: kernelnewbies@lists.kernelnewbies.org
Subject: what is the use of #ifndefs
Date: Tue, 21 Jul 2015 10:24:45 +0800 [thread overview]
Message-ID: <20150721022445.GA2368@debian> (raw)
In-Reply-To: <CAAGnT3auLPQqtOZv+4sdf4UyesdEz3tdPkzao0AyUmQ5C9Hbcg@mail.gmail.com>
On Mon, Jul 20, 2015 at 12:03:07PM +0200, Ahmed Soliman wrote:
> currently I started reading through the linux kernel and I started
> reading liunx/include/linux/list.h> I understood some of the functions
> but still I dont know what does these lines of code do
> #ifndef _LINUX_LIST_H
> #define _LINUX_LIST_H
> which exist at the very beginning of the file
> I also noticed that there is many similar ifndefs in almost any .h
> file in the kernel
> note that I understand wnat does ifndef do bu I dont understand what
> goal is it supposed to achieve at the beginning of the headerfile
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
The whole structure seems to
#ifndef ...
#define ...
.
.
.
#endif
next prev parent reply other threads:[~2015-07-21 2:24 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-20 10:03 what is the use of #ifndefs Ahmed Soliman
2015-07-20 15:55 ` leo kirotawa
2015-07-20 16:03 ` Stephan Müller
2015-07-20 16:11 ` Greg Freemyer
2015-07-20 17:00 ` anish singh
2015-07-21 2:24 ` Navy [this message]
2015-07-21 5:05 ` Raul Piper
2015-07-21 5:34 ` Amit Pandey
2015-07-21 7:01 ` Navy
2015-07-21 8:33 ` Bernd Petrovitsch
2015-07-21 19:44 ` Aruna Hewapathirane
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