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From: leichter@yale-com.UUCP (Jerry Leichter)
Newsgroups: net.lang.c,net.unix-wizards,net.wanted
Subject: Re: need info: %r in printf
Message-ID: <2151@yale-com.UUCP>
Date: Wed, 12-Oct-83 09:45:42 EDT
Article-I.D.: yale-com.2151
Posted: Wed Oct 12 09:45:42 1983
Date-Received: Thu, 13-Oct-83 10:14:29 EDT
References: fortune.1587
Lines: 31

"%r" is "Remote Format" in DECUS C; I don't know whether any other C's support
it.  Here is the relevant documentation from the DECUS C manual:

	Remote Format.  The next printf() argument is the format.  Note that
	this is not a subroutine.  The current format is not processed
	further.  For example:

		bug(args)
		{
			error("Error at %r",&args);
		}

	This routine might be called as follows:

		bug("Error %d at %s\n",val,name);

Note:  error() in DECUS C takes a printf-like argument, prints it to stderr,
then exits.  The use of "&args" is a standard hack for passing on multiple
arguments.

There is no general equivalent for %r that I know of.  You can probably get
some of the effect using the variable-number-of-arguments package.  In some
cases, you'll have to re-organize the code, perhaps to do multiple sprintf's.

BTW, the example above is rather silly, since the "bug" call shown will produce
a message of the form "Error at Error xxx at yyy".  However, the idea should
be clear...The only examples of %r I know of, as it happens, are in error
printers of this general form; in fact, I think error() itself may use %r
to call fprintf.
							-- Jerry
					decvax!yale-comix!leichter leichter@yale