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From: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Newsgroups: comp.lang.perl
Subject: Re: shortest self-reproducing Perl program
Message-ID: <7493@jpl-devvax.JPL.NASA.GOV>
Date: 21 Mar 90 00:49:28 GMT
References: <1990Mar20.203516.8429@iwarp.intel.com> <1990Mar20.215103.23101@agate.berkeley.edu>
Reply-To: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 30

In article <1990Mar20.215103.23101@agate.berkeley.edu> raymond@math.berkeley.edu (Raymond Chen) writes:
: >Any one liners?
: 
:  [[ don't put a newline at the end ]]
: 
: $s='$s=%c%s%c;printf$s,39,$s,39;';printf$s,39,$s,39;
: 
: Unfortunately, it doesn't work even though it should; the output is
: 
: $s='$s=%c%sc;printf$s,39,$s,39;';printf$s,39,$s,39;
: 	     ^ huh?
: 
: This happens with
: 
: 	$Header: perly.c,v 3.0.1.4 90/02/28 18:06:41 lwall Locked $
: 	Patch level: 12
: 
: on a VAX8700 running ULTRIX.
: 
: Was this fixed in one of the more recent patches?

Depends on how recent you think patch 16 is.   :-)

do_sprintf() was assuming that you wouldn't sprintf a string using itself
as the format, so it temporarily installed nulls in the string to
handle each % interpolation.  Obviously a bad assumption...

Life's a beach.  And then you dry.

Larry