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Posting-Version: version B 2.10.2 9/18/84; site watmath.UUCP
Path: utzoo!watmath!atbowler
From: atbowler@watmath.UUCP (Alan T. Bowler [SDG])
Newsgroups: net.lang.c
Subject: Re: re: how has C bitten you?
Message-ID: <16150@watmath.UUCP>
Date: Sun, 11-Aug-85 14:57:22 EDT
Article-I.D.: watmath.16150
Posted: Sun Aug 11 14:57:22 1985
Date-Received: Wed, 14-Aug-85 02:28:35 EDT
References: <505@brl-tgr.ARPA>
Reply-To: atbowler@watmath.UUCP (Alan T. Bowler [SDG])
Organization: U of Waterloo, Ontario
Lines: 19
Summary: 

In article <505@brl-tgr.ARPA> mbarker@BBNZ.ARPA (Michael Barker) writes:
>>So, printf can never get a float as an argument, it always gets a double.
>>Therefore, %lf or %F are meaningless to printf.
>>
>>Brian Jones  aka  {ihnp4,}!drutx!qwerty  @  AT&T-IS
>
>Brian (et al) - the reasoning is correct, but printf could easily be changed to
>accept %lf or %F (or any useful convention) as formatting directions for a
>value with the knowledge that the value will *actually* be a double.  Let's try
I thought that the implicit promotion of float to double on passing
an argument was one of the things that was going away with the
new C standard.   It certainly has been high on my personal hit list.
  I grant that there was a reasonable case for it when C was just for
PDP-11's.  But these days when there is a good possibility that
floating point is being handled by a software implementation of
the IEEE standard, it is a loser.  In this situation the conversion
between float and double is a reasonably expensive operation,
and really should only be done when the programmer explicitly asks for it.