From newton@ficus.frogspace.net

The Perl debugger outputs strings containing the character
ctrl-\ wrongly when using the "x" command. For example,
x chr(28) results in "\c\" and x "\c\\" results in "\c\\\".
The results, however, are not valid Perl and will result in
"string terminator not found before end of line".

(Pesky character, that.)

Site configuration information for perl 5.00503:

Configured by frogleg at Sun Aug  8 13:32:51 EDT 1999.

Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration:
  Platform:
    osname=linux, osvers=5.2, archname=i686-linux
    uname='linux ficus.frogspace.net 2.2.6-ac3 #2 thu aug 5 09:35:04 edt 1999 i686 unknown '
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef useperlio=undef d_sfio=undef
  Compiler:
    cc='gcc', optimize='-O2', gccversion=2.7.2.3
    cppflags='-Dbool=char -DHAS_BOOL -I/usr/local/include'
    ccflags ='-Dbool=char -DHAS_BOOL -I/usr/local/include'
    stdchar='char', d_stdstdio=define, usevfork=false
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    alignbytes=4, usemymalloc=n, prototype=define
  Linker and Libraries:
    ld='gcc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lnsl -lndbm -lgdbm -ldb -ldl -lm -lc -lposix -lcrypt
    libc=, so=so, useshrplib=false, libperl=libperl.a
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic'
    cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'

Locally applied patches:
    


@INC for perl 5.00503:
    /usr/local/lib/perl5/5.00503/i686-linux
    /usr/local/lib/perl5/5.00503
    /usr/local/lib/perl5/site_perl/5.005/i686-linux
    /usr/local/lib/perl5/site_perl/5.005
    .


Environment for perl 5.00503:
    HOME=/home/newton
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:/usr/sbin:/home/newton:.
    PERL_BADLANG (unset)
    SHELL=/bin/bash

From @schwern

[newton@​ficus.frogspace.net - Thu Apr 05 19​:58​:47 2001]​:
The Perl debugger outputs strings containing the character
ctrl-\ wrongly when using the "x" command. For example,
x chr(28) results in "\c\" and x "\c\\" results in "\c\\\".
The results, however, are not valid Perl and will result in
"string terminator not found before end of line".

The problem is in dumpvar.pl which x uses. The attached patch fixes this.

From @schwern

--- lib/dumpvar.pl	2005/07/12 22:27:33	1.1
+++ lib/dumpvar.pl	2005/07/12 22:34:03
@@ -80,13 +80,21 @@
 	} elsif ($unctrl eq 'quote') {
 	  s/([\"\\\$\@])/\\$1/g if $tick eq '"';
 	  s/\033/\\e/g;
-	  s/([\000-\037\177])/'\\c'.chr(ord($1)^64)/eg;
+	  s/([\000-\037\177])/'\\c'._escaped_ord($1)/eg;
 	}
 	$_ = uniescape($_);
 	s/([\200-\377])/'\\'.sprintf('%3o',ord($1))/eg if $quoteHighBit;
 	($noticks || /^\d+(\.\d*)?\Z/) 
 	  ? $_ 
 	  : $tick . $_ . $tick;
+}
+
+# Ensure a resulting \ is escaped to be \\
+sub _escaped_ord {
+    my $chr = shift;
+    $chr = chr(ord($chr)^64);
+    $chr =~ s{\\}{\\\\}g;
+    return $chr;
 }
 
 sub ShortArray {

From @Tux

On Tue, 12 Jul 2005 15​:36​:54 -0700, "Michael G Schwern via RT"
<perlbug-followup@​perl.org> wrote​:

[newton@​ficus.frogspace.net - Thu Apr 05 19​:58​:47 2001]​:
The Perl debugger outputs strings containing the character
ctrl-\ wrongly when using the "x" command. For example,
x chr(28) results in "\c\" and x "\c\\" results in "\c\\\".
The results, however, are not valid Perl and will result in
"string terminator not found before end of line".

The problem is in dumpvar.pl which x uses. The attached patch fixes this.

Thanks, applied as change #25130

--
H.Merijn Brand Amsterdam Perl Mongers (http​://amsterdam.pm.org/)
using Perl 5.6.2, 5.8.0, 5.8.5, & 5.9.2 on HP-UX 10.20, 11.00 & 11.11,
AIX 4.3 & 5.2, SuSE 9.2 & 9.3, and Cygwin. http​://www.cmve.net/~merijn
Smoking perl​: http​://www.test-smoke.org, perl QA​: http​://qa.perl.org
reports to​: smokers-reports@​perl.org, perl-qa@​perl.org

@schwern - Status changed from 'open' to 'resolved'