understanding FLT_DIG

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Article #3330

#3330

From: Steve Emmerson
Date: Tue, 05 Jan 1993 23:06

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Hi,

I'm having trouble understanding FLT_DIG, which is defined in <float.h>,
According to section 2.2.4.2.2 of the ANSI standard, FLT_DIG is given by
the following on base-2 machines:

	FLT_DIG = (int)((p-1)*log10(2))

where `p' is the precision (the number of base-2 digits in the
significand).

On a hypothetical base-2 machine with 4 bits of precision, the above yields
0 for FLT_DIG.  Yet, those 4 bits can represent the integral values 1
through 9 exactly.  Thus, shouldn't FLT_DIG be 1?

Eagerly awaiting enlightenment.
--

Steve Emmerson        steve@unidata.ucar.edu        ...!ncar!unidata!steve

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Path: arc1-ca.pugleaf.net!sparky!uunet!europa.asd.contel.com!gatech!asuvax!ncar!steve
From: steve@unidata.ucar.edu (Steve Emmerson)
Subject: understanding FLT_DIG
Message-ID: <steve.726275211@unidata.ucar.edu>
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Date: Tue, 5 Jan 1993 23:06:51 GMT
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