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From: ubi@sri-unix.ARPA (Ron Ueberschaer)
Newsgroups: comp.bugs.sys5,comp.sys.hp
Subject: Re: pow(3M) may have a bug or undocumented limitation
Message-ID: <2510@sri-unix.ARPA>
Date: Mon, 18-May-87 00:35:09 EDT
Article-I.D.: sri-unix.2510
Posted: Mon May 18 00:35:09 1987
Date-Received: Mon, 18-May-87 04:02:27 EDT
References: <226@cogent.UUCP>
Reply-To: ubi@sri-unix.UUCP (Ron Ueberschaer)
Distribution: world
Organization: SRI, Menlo Park, CA.
Lines: 26
Keywords: x^y y<0 DOMAIN error
Xref: mnetor comp.bugs.sys5:120 comp.sys.hp:148

> [problem with doing]  pow(2, -12)
When passing integer arguments to pow(), or any other
math function requiring floating points (double, actually),
be sure that you either cast the variable, e.g.

	pow((double) i, (double) j)    ,

or explicitely type the decimal point, e.g.

	pow(2., -12.)    .

While most compilers handle implicit type conversion in
*expressions*, arguments to *functions* require more care.

The particular problem you are having bit me once before,
although I didn't get a useful runtime error message, just
the old "(core dumped)."  I don't think the negative exponent
is the problem.  A negative mantissa, however, will not work,
even if the exponent is integer.

			Hope this helps,

			Ron Ueberschaer		
			SRI International 	Menlo Park, CA
			...!{hplabs,rutgers}!sri-unix!ubi
			ubi@sri-unix.UUCP