From: Arnd Bergmann <arnd@arndb.de>
To: Jaswinder Singh Rajput <jaswinder@kernel.org>
Subject: Re: Confusion in usr/include/asm-generic/fcntl.h
Date: Mon, 26 Jan 2009 16:53:32 +0100
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       Sam Ravnborg <sam@ravnborg.org>
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On Friday 23 January 2009, Jaswinder Singh Rajput wrote:
> 
> So who wins the race for CONFIG_64BIT and will be right candidate for
> usr/include/asm-generic/fcntl.h:
> 
> 1. #if BITS_PER_LONG == 64

namespace pollution => doesn't work

> OR
> 
> 2. #if __BITS_PER_LONG == 64

my suggestion, looks good

> 
> OR
> 
> 3. #ifdef __LP64__

Should work, but not sure if all compilers get it right

> 
> OR
> 
> 4. #if __SIZEOF_POINTER__ == 8

Never heard of this, but seems fine, probably __SIZEOF_LONG__
would be more logical (but with identical results)

> 
> OR
> 
> 5. #if LONG_MAX > 2147483647L

requires #include <stdint.h>, which pollutes the namespace => doesn't work


> OR
> 
> 6. #ifdef __64BIT

Dangerous, as explained.

	Arnd <><
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