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From: hubert@entropy.UUCP (Steve Hubert)
Newsgroups: net.bugs.4bsd
Subject: libm---log(negative)
Message-ID: <130@entropy.UUCP>
Date: Fri, 8-Feb-85 14:04:10 EST
Article-I.D.: entropy.130
Posted: Fri Feb  8 14:04:10 1985
Date-Received: Sun, 10-Feb-85 03:11:22 EST
Distribution: net
Organization: UW MathStat, Seattle
Lines: 16

Libm says log(negative) = -HUGE and sqrt(negative) = 0.
Both set errno = EDOM which is reasonable.  I guess the values
0 and -HUGE must come from the idea that the functions should
be continuous at zero or some voodoo like that.

If I am not mistaken, Fortran programmers are used to being yelled at
when they try to pass an out-of-domain argument to a function.
C programmers, as always, are a different story.  Anyway, does anyone,
besides me, think it would be a good idea to explicitly warn the user
when s/he attempted to call log with a negative argument?  If so,
have you come up with a smooth way of doing it?

Steve Hubert
 Dept. of Stat., U. of Wash, Seattle
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