From owner-freebsd-hackers  Thu Oct 10 12:28:45 2002
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Date: Thu, 10 Oct 2002 12:26:43 -0700
From: Terry Lambert <tlambert2@mindspring.com>
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To: Giorgos Keramidas <keramida@ceid.upatras.gr>
Cc: Garrett Wollman <wollman@lcs.mit.edu>,
	Craig Rodrigues <rodrigc@attbi.com>, freebsd-standards@freebsd.org,
	freebsd-hackers@freebsd.org
Subject: Re: Problem detecting POSIX symbolic constants
References: <20021009222307.A9894@attbi.com> <200210100549.g9A5nFLn060516@khavrinen.lcs.mit.edu> <3DA5354F.9BB3E54B@mindspring.com> <20021010112434.GS21391@hades.hell.gr>
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Giorgos Keramidas wrote:
> > I think the first is safer, in that if "#if" is not supported, it
> > being an undefined preprocessor directive would be non-fatal,
> > being in an uncompiled "#ifdef" block...
> 
> Well, almost.  There is one exception.  A compiler that doesn't support
> #if but happens to run in an environment that has _POSIX_REALTIME_SIGNALS
> defined and equal to -1.

You can always wrap the whole thing with a POSIX test, which
would dictate the preprocessor support, as well, I think.

-- Terry

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