From @eserte

This is a bug report for perl from eserte@​vran.herceg.de,
generated with the help of perlbug 1.33 running under perl v5.7.2.

I'm not sure whether this is a Perl/Tk or perl problem​:

In Perl/Tk there is a call to pregexec with a NULL as 6th argument​:

return pregexec(re,string,string+strlen(string),start,0,NULL,1);

(this is in file tkGlue.c).

In perl's Perl_regexec_flags function, a core will be dumped at line
1427​:

  bool do_utf8 = DO_UTF8(sv);

The problem is fixed if I change the line to​:

  bool do_utf8 = sv && DO_UTF8(sv);

Regards,
  Slaven

Flags​:
  category=core
  severity=medium

Site configuration information for perl v5.7.2​:

Configured by eserte at Sat Feb 9 22​:33​:02 CET 2002.

Summary of my perl5 (revision 5.0 version 7 subversion 2 patch 14574) configuration​:
  Platform​:
  osname=freebsd, osvers=4.3-stable, archname=i386-freebsd-64int
  uname='freebsd vran.herceg.de 4.3-stable freebsd 4.3-stable #6​: mon jul 9 11​:49​:47 cest 2001 root@​vran.herceg.de​:vranhomesrcfreebsd-4srcsyscompilevran i386 '
  config_args='-Doptimize=-g -DPERL_DEBUGGING_MSTATS -Dusemymalloc=y -Dprefix=/usr/perl5.7.2d -D usedevel=define -de -D hintfile=myfreebsd'
  hint=recommended, useposix=true, d_sigaction=define
  usethreads=undef use5005threads=undef useithreads=undef usemultiplicity=undef
  useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
  use64bitint=define use64bitall=undef uselongdouble=undef
  usemymalloc=y, bincompat5005=define
  Compiler​:
  cc='cc', ccflags ='-DHAS_FPSETMASK -DHAS_FLOATINGPOINT_H -DDEBUGGING -fno-strict-aliasing -I/usr/local/include',
  optimize='-g -DPERL_DEBUGGING_MSTATS',
  cppflags='-DHAS_FPSETMASK -DHAS_FLOATINGPOINT_H -DDEBUGGING -fno-strict-aliasing -I/usr/local/include'
  ccversion='', gccversion='2.95.3 [FreeBSD] 20010315 (release)', gccosandvers=''
  intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=12345678
  d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
  ivtype='long long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
  alignbytes=4, prototype=define
  Linker and Libraries​:
  ld='cc', ldflags ='-Wl,-E -L/usr/local/lib'
  libpth=/usr/lib /usr/local/lib
  libs=-lbind -lgdbm -ldb -lm -lc -lcrypt -lutil
  perllibs=-lbind -lm -lc -lcrypt -lutil
  libc=, so=so, useshrplib=false, libperl=libperl.a
  Dynamic Linking​:
  dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags=' '
  cccdlflags='-DPIC -fpic', lddlflags='-shared -L/usr/local/lib'

Locally applied patches​:
  DEVEL14574

@​INC for perl v5.7.2​:
  lib
  /usr/perl5.7.2d/lib/5.7.2/i386-freebsd-64int
  /usr/perl5.7.2d/lib/5.7.2
  /usr/perl5.7.2d/lib/site_perl/5.7.2/i386-freebsd-64int
  /usr/perl5.7.2d/lib/site_perl/5.7.2
  /usr/perl5.7.2d/lib/site_perl
  .

Environment for perl v5.7.2​:
  HOME=/home/e/eserte
  LANG (unset)
  LANGUAGE (unset)
  LC_ALL=de_DE.ISO_8859-1
  LD_LIBRARY_PATH (unset)
  LOGDIR (unset)
  PATH=/usr/X11R6/bin​:/usr/X11/bin​:/usr/local/bin​:/usr/bin​:/bin​:/usr/gnu/bin​:/usr/TeX/bin​:/usr/local/sbin​:/usr/sbin​:/sbin​:/usr/local/pilot/bin​:/home/e/eserte/bin/FreeBSD​:/home/e/eserte/bin/sh​:/home/e/eserte/bin​:/usr/X386/bin​:/usr/games​:/home/e/eserte/devel
  PERL_BADLANG (unset)
  SHELL=/usr/local/bin/tcsh

From @vanstyn

Slaven Rezic <eserte@​vran.herceg.de> wrote​:
:I'm not sure whether this is a Perl/Tk or perl problem​:
[...]
:
:In perl's Perl_regexec_flags function, a core will be dumped at line
:1427​:
: bool do_utf8 = DO_UTF8(sv);

That's a problem with the regexp engine.

:The problem is fixed if I change the line to​:
:
: bool do_utf8 = sv && DO_UTF8(sv);

That's fine as a starting point, but I suspect we need the ability to
match on an SV-less UTF8 string as well. Perhaps we should add a flag
for the purpose? Then the above could be​:
  bool do_utf8 = sv ? DO_UTF8(sv) : flags & REXEC_UTF8;

Note also that this would require some fixup for the debugging (which
assumes an sv if utf8) and for screaminstr() calls (which assume an sv
if REXEC_SCREAM).

Hugo

From [Unknown Contact. See original ticket]

Hugo Van Der Sanden <hv@​crypt0.demon.co.uk> writes​:

Slaven Rezic <eserte@​vran.herceg.de> wrote​:
​:I'm not sure whether this is a Perl/Tk or perl problem​:
[...]
​:
​:In perl's Perl_regexec_flags function, a core will be dumped at line
​:1427​:
​: bool do_utf8 = DO_UTF8(sv);

That's a problem with the regexp engine.

And Tk ;-)

​:The problem is fixed if I change the line to​:
​:
​: bool do_utf8 = sv && DO_UTF8(sv);

That's fine as a starting point,

There are other references to sv further down - some guarded, some not
(in my quick scan).

but I suspect we need the ability to
match on an SV-less UTF8 string as well.

I have no real problem requiring an SV for this.
I just patched Tk to construct one.
What mislead me was that SV * parameter used to be called 'screamer'
and was something to do with 'study'. I never understood that and did
not known that SV * _was_ the string.

When Unicode-aware Tk gets out it will only ever use this on UTF-8 strings.

Perhaps we should add a flag
for the purpose? Then the above could be​:
bool do_utf8 = sv ? DO_UTF8(sv) : flags & REXEC_UTF8;

Note also that this would require some fixup for the debugging (which
assumes an sv if utf8) and for screaminstr() calls (which assume an sv
if REXEC_SCREAM).

Hugo
--
Nick Ing-Simmons
http​://www.ni-s.u-net.com/

From @khwilliamson

Is this still an issue?
--
Karl Williamson

I'm closing this. I asked two years ago if this is still an issue, without response. Further investigation reveals that this parameter may no longer be NULL, since
commit 4373e32
Author: Andy Lester andy@petdance.com
Date: Wed May 4 23:55:00 2005 +0000