Purpose of using __be16 inside a data structure?

[Kevin O'Gorman]

On Tue, Aug 9, 2011 at 12:25 AM, 陳國成 <gcchen.org at gmail.com> wrote:

> Hi all,
>
> Please tell me the difference between using unsigned short and __be16 to
> declear a variable in a data structure.
>
> The purpose of this and similar artificial types is to allow the code to be
written in an architecture-independent way.  The name is chosen to reflect
the behavior (signedness, capacity, precision, etc) that is desired, and the
headers for each architecture typedef it to a standard C type that
accomplishes this goal.  From the name, I expect this to be a 16-bit type.
It may have other attributes, such as a specific endianness (unusual except
in networking), or specific signedness.  Except on unusual or antique
architectures, I would expect this one to resolve to "short" or "unsigned
short", but other possibilities exist.

What you should usually do is to find the typedef of __be16 in the headers
and see if there is a clue to what use this type is intended for.

-- 
Kevin O'Gorman, PhD
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