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Date: Fri, 9 Jan 2004 17:42:44 +0100
From: Stefan Farfeleder <stefan@fafoe.narf.at>
To: Bruce Evans <bde@zeta.org.au>
Message-ID: <20040109164241.GA596@wombat.fafoe.narf.at>
References: <200401081510.39015.linimon@lonesome.com>
	<20040110012527.S18300@gamplex.bde.org>
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cc: Mark Linimon <linimon@lonesome.com>
cc: freebsd-standards@freebsd.org
Subject: Re: Fwd: Re: ports/52016: New port: lang/harbour -
	AClipper-compatible compiler
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On Sat, Jan 10, 2004 at 02:03:57AM +1100, Bruce Evans wrote:

> - at least old standards seem to permit feature test macros to have no
>   value (they may be empty, or perhaps more bizarre).  The "+ 0" in the
>   above is to handle this case, so that feature test with an empty value
>   work the same as ones with value 0.

[...]

> #if _POSIX_SYNCHRONIZED_IO + 0 > 0

Undefined identifiers are replaced with 0 in a #if directive.  Maybe
some ancient pre-C90 compilers didn't do that, but I think they can be
ignored these days.

Regards,
Stefan Farfeleder