Newsgroups: comp.lang.c
Path: utzoo!henry
From: henry@zoo.toronto.edu (Henry Spencer)
Subject: Re: FLOATING NULL?
Message-ID: <1991May28.153655.24199@zoo.toronto.edu>
Date: Tue, 28 May 1991 15:36:55 GMT
References: <13223@uhccux.uhcc.Hawaii.Edu>
Organization: U of Toronto Zoology

In article <13223@uhccux.uhcc.Hawaii.Edu> karl@wiliki.UUCP (Karl Ihrig) writes:
>...blank spots in my real world data.  I am totally baffled.  How do I
>mark the float element of the array as null, blank, or not
>available?

There is no portable way except allocating a separate flag for each of
your float values.  C does not guarantee the existence of any "blank" value
in floating point, and indeed a good many machines have no such special
value.  If you are willing to constrain your code to run on machines using
IEEE floating point, you could use a NaN value... but there is no standard
way of generating such a value or testing for it.
-- 
"We're thinking about upgrading from    | Henry Spencer @ U of Toronto Zoology
SunOS 4.1.1 to SunOS 3.5."              |  henry@zoo.toronto.edu  utzoo!henry