cannot alias tied filehandle

[p5pRT]

Migrated from rt.perl.org#1739 (status was 'resolved')

Searchable as RT1739$

[p5pRT]

From sey@tera.kyoto.jkc.co.jp

I cannot alias a tied filehandle with type glob assignment.

  tie *H, 'Test';
  *K = *H;
  print "*H is tied '",tied(*H),"'\n";
  print "*K is tied '",tied(*K),"'\n";
  sub Test​::TIEHANDLE { bless {}, shift; }

This prints as follows.

  *H is tied 'Test=HASH(0xba0c40)'
  *K is tied ''

I have an alternate way as follows. But it is not usable for practical
use.

  tie *H, 'Test';
  tie *K, 'AliasTieHandle', tied(*H);
  print "*H is tied '",tied(*H),"'\n";
  print "*K is tied '",tied(*K),"'\n";
  sub Test​::TIEHANDLE { bless {}, shift; }
  sub AliasTieHandle​::TIEHANDLE { shift; shift; }

Perl Info

Site configuration information for perl 5.00503:

Configured by sey at Mon Nov  1 16:38:39 JST 1999.

Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration:
  Platform:
    osname=freebsd, osvers=2.2.8-release, archname=i386-freebsd
    uname='freebsd tera.kyoto.jkc.co.jp 2.2.8-release freebsd 2.2.8-release #0: mon nov 30 06:34:08 gmt 1998 jkh@time.cdrom.com:usrsrcsyscompilegeneric i386 '
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef useperlio=undef d_sfio=undef
  Compiler:
    cc='cc', optimize='-g', gccversion=2.7.2.1
    cppflags='-DDEBUGGING -I/usr/local/include'
    ccflags ='-DDEBUGGING -I/usr/local/include'
    stdchar='char', d_stdstdio=undef, usevfork=true
    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='ld', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /usr/lib
    libs=-lgdbm -lm -lc -lcrypt
    libc=/usr/lib/libc.so.3.1, so=so, useshrplib=false, libperl=libperl.a
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags=' '
    cccdlflags='-DPIC -fpic', lddlflags='-Bshareable  -L/usr/local/lib'

Locally applied patches:
    jperl5.005_03-990822.pat - end of week


@INC for perl 5.00503:
    /usr/local/lib/perl5/5.00503/i386-freebsd
    /usr/local/lib/perl5/5.00503
    /usr/local/lib/perl5/site_perl/5.005/i386-freebsd
    /usr/local/lib/perl5/site_perl/5.005
    .


Environment for perl 5.00503:
    HOME=/home/sey
    LANG=ja_JP.EUC
    LANGUAGE (unset)
    LC_ALL=C
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/games:/usr/local/bin:/usr/X11R6/bin:/home/sey/bin
    PERL_BADLANG (unset)
    SHELL=/usr/local/bin/tcsh

[p5pRT]

From [Unknown Contact. See original ticket]

This appears to still be true under bleadperl 8101.

This is a bug report for perl from sey@​tera.kyoto.jkc.co.jp,
generated with the help of perlbug 1.26 running under perl 5.00503.

-----------------------------------------------------------------
[Please enter your report here]
I cannot alias a tied filehandle with type glob assignment.

  tie *H, 'Test';
  *K = *H;
  print "*H is tied '",tied(*H),"'\n";
  print "*K is tied '",tied(*K),"'\n";
  sub Test​::TIEHANDLE { bless {}, shift; }

This prints as follows.

  *H is tied 'Test=HASH(0xba0c40)'
  *K is tied ''

I have an alternate way as follows. But it is not usable for practical
use.

  tie *H, 'Test';
  tie *K, 'AliasTieHandle', tied(*H);
  print "*H is tied '",tied(*H),"'\n";
  print "*K is tied '",tied(*K),"'\n";
  sub Test​::TIEHANDLE { bless {}, shift; }
  sub AliasTieHandle​::TIEHANDLE { shift; shift; }

[p5pRT]

From @mjdominus

I cannot alias a tied filehandle with type glob assignment.

tie *H, 'Test';
*K = *H;

I thought that the reson this didn't work is that the glob was copied,
similar to the way

  tie $H, 'Text';
  $K = $H;

does not leave $K tied.

Some time ago I reported what seems to be a related problem​:

  bless \*H => 'Test';
  *K = *H;

and *K is not blessed. I was told that this was not a bug.

I will hunt up the mail if anyone thinks it would be illuminating.

[p5pRT]

From [Unknown Contact. See original ticket]

I'll close it.

-spp

Lightning flashed, thunder crashed and Mark-Jason Dominus <mjd@​plover.com> whis
pered​:
|
| > I cannot alias a tied filehandle with type glob assignment.
| >
| > tie *H, 'Test';
| > *K = *H;
|
| I thought that the reson this didn't work is that the glob was copied,
| similar to the way
|
| tie $H, 'Text';
| $K = $H;
|
| does not leave $K tied.
|
| Some time ago I reported what seems to be a related problem​:
|
| bless \*H => 'Test';
| *K = *H;
|
| and *K is not blessed. I was told that this was not a bug.
|
| I will hunt up the mail if anyone thinks it would be illuminating.

[p5pRT]

From @mjdominus

I'll close it.

I wasn't suggesting that you close it. I was hoping that someone with
more expertise would weigh in.

[p5pRT]

From @floatingatoll

So, how do I go about making a copy of $H or *H that retains all the special
stuff like ties and blessedness? As this is not a bug, I can't see any way
to do it.

R.

I thought that the reson this didn't work is that the glob was copied,
similar to the way

    tie $H\, 'Text';
    $K = $H;

does not leave $K tied.

Some time ago I reported what seems to be a related problem​:

    bless \\\*H => 'Test';
    \*K = \*H;

and *K is not blessed. I was told that this was not a bug.

R.

[p5pRT]

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