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Re: [avr-libc-dev] RFC: avr/bits.h

From: Joerg Wunsch
Subject: Re: [avr-libc-dev] RFC: avr/bits.h
Date: Tue, 1 Mar 2005 21:46:19 +0100
User-agent: Mutt/

As Erik Walthinsen wrote:

> The first macro is BIT(), requested by a number of people as a
> replacement for the not-so-obviously-named _BV(), which is nominally
> an internal-use-only macro according to its leading underscore.

It's correct that the identifier _BV belongs to those that are
reserved for `the implementation', but that had been chosen
deliberately.  It prevents the header file (<avr/io.h>) from
potentially clashing with the name BV which is a legitimate name for
the application name space.  As avr/io.h is needed in virtually any
application, Marek decided that way to avoid the clash.

Of course, when moving it out to avr/bits.h, the usage of BIT() is
fine as well.  If an application choses to use avr/bits.h, it has to
abide to its rules.  Unlike for avr/io.h, any application is free to
not use avr/bits.h if they don't like this policy.

cheers, J"org               .-.-.   --... ...--   -.. .  DL8DTL

http://www.sax.de/~joerg/                        NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)

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