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From: ado@sauna.hut.fi (Andre Dolenc)
Newsgroups: comp.lang.c
Subject: # to the n-th power
Message-ID: <1990Nov5.135212.1700@santra.uucp>
Date: 5 Nov 90 13:52:12 GMT
Sender: news@santra.uucp (Cnews - USENET news system)
Organization: Helsinki University of Technology, Finland
Lines: 25


(1) Since my last posting I have learned that the source code to the
    math functions (libm) of 4.3 BSD are publicly available and may
    be obtained by anon. ftp from several sites, eg.
      funic.funet.fi in ~ft/pub/unix/bsd-sources/src/usr.lib/libm
    which is a copy of an anon. ftp directory in uunet.uu.net.
    Read the copyright notice before using them.
(2) Looking into "pow" one learns that to figure out if "y"
    in "pow(x,y)" is an integer is reduced to:
       t=drem(x,two);
       if ((t == zero) || (copysign(t,one) == one)) then "y is int".
    Now, the code which implements "drem" is not trivial. Therefore,
    I withdraw my question "How do we decide if y is an integer?".
(3) My previous posting contains (at least) one error. The multiple
    precision function "pow" is defined under SunOs in "misc. lib
    functions", MP(3X), *not* under Ultrix.
    The problem is that the name obviously conflicts with the math
    function "double pow(double x, double y)". Isn't dum to have
    2 (system) library functions with the same name?
In the hope of not having wasted too much bandwidth,
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Andre' Dolenc                              Helsinki University of Technology
Research Associate                         TKO, Otakaari 1A, Espoo
Email (Internet): ado@sauna.hut.fi         SF-02150  Finland
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