Re: R-alpha: Probably <float.h> instead of <values.h> for an automatic .Machine

Luke Tierney (luke@stat.umn.edu)
Wed, 4 Dec 1996 13:16:44 -0600 (CST)


From: Luke Tierney <luke@stat.umn.edu>
Message-Id: <9612041916.AA27586@nokomis.stat.umn.edu>
Subject: Re: R-alpha: Probably <float.h> instead of <values.h> for an automatic .Machine
To: bates@stat.wisc.edu (Douglas Bates)
Date: Wed, 4 Dec 1996 13:16:44 -0600 (CST)
In-Reply-To: <m0vVMQu-000hhyC@franz.stat.wisc.edu> from "Douglas Bates" at Dec 4, 96 12:52:36 pm

> 
> I checked with some ANSI gurus here are work and we can't see that
> either <values.h> or <float.h> are required by the ANSI standard.
> However, <float.h> is required by the POSIX standard and it appears to
> define pretty well everything that is needed in the .Machine object
> except (naturally) for the maximum integer and other values based on
> the integer representation.
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According to Harbison and Steele, 3rd Ed., which is what I happen to
have handy, ANSI C requires that the floating point constants be
defined in float.h and the integer ones in limits.h. Don't know how
authoritative that is, or whether it might have changed in ANSI or ISO
C since 1991. The 4th is based on ISO C, but I don't have that handy.

luke
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