Does GCC really recognize __attribute__ ((bitwise))?

Thu Mar 27 12:17:00 GMT 2008

Hi Ho!

When browsing the Linux kernel's source code, I noticed a variable
definition like:

typedef __u64 __bitwise __be64;

Being curious about __bitwise, I found it out to be:

#define __bitwise __bitwise__

that finally turned out to be:

#define __bitwise__ __attribute__((bitwise))

Since it was __attribute__, I tried to find its documentation in GCC texinfo
file. But, I couldn't find one. Even I have tried to find it out in the Internet.
But, I still couldn't find one.

Is it a custom defined attribute? If it is, is the way to do such thing
documented in GCC texinfo? If it is not, why does it not described in GCC texinfo

Thank you very much.

Best regards,
Eus (FSF member #4445)

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