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From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.lang.c,net.unix-wizards,net.wanted
Subject: Re: need info: %r in printf
Message-ID: <3251@utzoo.UUCP>
Date: Thu, 13-Oct-83 16:03:23 EDT
Article-I.D.: utzoo.3251
Posted: Thu Oct 13 16:03:23 1983
Date-Received: Thu, 13-Oct-83 16:03:23 EDT
References: fortune.1587, <2151@yale-com.UUCP>
Organization: U of Toronto Zoology
Lines: 18

The reason (well, I think the major reason) why %r has gone away in
recent years is that it is not really portable.  The trick of calling
a routine with a variable number of parameters, while the routine
declares only one parameter and invokes printf %r with the address
of that parameter, is nifty and neat but absolutely requires some
highly machine-dependent assumptions about calling sequences.  There
is no truly machine-independent way to do this trick without help from
the language, help which C does not provide.  The only thing you can
really do about it is to sprintf into a string and then pass that.
(Yes, I know, it's not as convenient.)

Please, no questions about why a machine-dependent construct like this
is in DECUS C.  Either they didn't know what they were doing, or they
didn't care (anyone using a DEC operating system obviously isn't worried
about portability anyway, right?).
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry