From mboxrd@z Thu Jan  1 00:00:00 1970
From: p.ittershagen@googlemail.com (Philipp Ittershagen)
Date: Thu, 19 Apr 2012 09:10:33 +0200
Subject: Include guard macro query
In-Reply-To: <CAE6Wm-tjXTDoi_hMNgLyuZcPSVags-9uKj5Nu_NDJTCA4tO=Sg@mail.gmail.com>
References: <CAE6Wm-tjXTDoi_hMNgLyuZcPSVags-9uKj5Nu_NDJTCA4tO=Sg@mail.gmail.com>
Message-ID: <20120419071033.GA9970@peter>
To: kernelnewbies@lists.kernelnewbies.org
List-Id: kernelnewbies.lists.kernelnewbies.org

On Thu, Apr 19, 2012 at 12:24:42PM +0530, Pritam Bankar wrote:
> Hi,
> 
> In Linux code we add a guard macro to avoid multiple declarations of
> identifiers.
> But I see some macros defined with trailing underscores.
> e.g. In arch/x86/include/asm/
> 
> Normally it is defined like,
> 
>  #ifndef _ASM_X86_ALTERNATIVE_H
>  #define _ASM_X86_ALTERNATIVE_H
> 
> But in some files I see trailing underscore after H ,
> 
> e.g. arch/x86/include/asm/intel_scu_ipc.h
> 
> 
> #ifndef _ASM_X86_INTEL_SCU_IPC_H_
> #define  _ASM_X86_INTEL_SCU_IPC_H_
> 
> There are others files also
> arch/x86/include/asm/irqflags.h
> http://lxr.linux.no/#linux+v3.3.2/arch/x86/include/asm/probe_roms.h
> 
> 
> DOES THIS TRAILING UNDERSCORE HAS SPECIAL MEANING ???

My guess: No.

Greetings,

  Philipp