#define sentinels with __FILE__

[Mathieu Malaterre <mathieu.malaterre@xxxxxxxxx>]

Hi there,

I've always assumed (before #pragma once), that sentinels were written like:

https://en.wikipedia.org/wiki/Include_guard#Use_of_.23include_guards

However grepping the linux source code I see:

$ cat sound/soc/samsung/pcm.h
#ifndef __S3C_PCM_H
#define __S3C_PCM_H __FILE__
<...>
#endif /* __S3C_PCM_H */

Why would any use:

#define __S3C_PCM_H __FILE__

instead of the simpler:

#define __S3C_PCM_H

This is not a copy/paste error, as I can find other references:

$ grep -r "#define" * | grep "_H " | grep __FILE|wc
     63     189    4996

Thanks,
-- 
Mathieu