DrWhy has asked for the wisdom of the Perl Monks concerning the following question:

Or perhaps the question is, is it possible at all? I would like to create a function that can take a file name or a previously opened generic perl filehandle and turn that into and IO::All object for processing. I haven't been able to create a usable IO::All object from a filehandle to this point. Here are some of the scenarios I've tried: 

use IO::All; 
use IO::File; 
open G, '<test.txt'; 
$h = IO::File->new_from_fd(fileno(*G{IO}), 'r'); 
$i = io($h); 
print $i->getline

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The docs of IO::All seem to imply that this should work, but when I run this (Win XP, ActiveState Perl 5.8.8, IO:All v0.33), I get: 

Can't call method "opened" on an undefined value at C:/perl/site/lib/I
+O/All/File.pm line 78.

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I've also tried variations without the IO::File intermediary, i.e., $i = io(*G{IO}), $i = io(\*G), $i = io->handle(*G), all to no avail.

Has anyone been down the path before and have a workable solution to this?

Update: This is now in RT.

Thanks,

--DrWhy

"If God had meant for us to think for ourselves he would have given us brains. Oh, wait..."

Replies are listed 'Best First'.
Re: How do I create an IO::All object from a pre-existing filehandle
by almut (Canon) on Jun 11, 2009 at 16:05 UTC

    The problem apparently is that it is being checked if $self->_handle is defined, but then ->opened is being called on $self->io_handle, which is undefined in your case. 

        if (defined $self->pathname) {
        $self->io_handle(IO::File->new);
        $self->io_handle->open($self->pathname, @args) 
          or $self->throw($self->open_msg);
    }
    elsif (defined $self->_handle and
           not $self->io_handle->opened   # <-- line 88
          ) {
        # XXX Not tested
        $self->io_handle->fdopen($self->_handle, @args);
    }

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    I think that piece of code should be 

        ...
    elsif (defined $self->_handle) {
        if ($self->_handle->opened) {  # already open ? --> set/use it
            $self->io_handle($self->_handle);
        } else {                       # not open       --> open it
            # XXX Not tested
            $self->io_handle->fdopen($self->_handle, @args);
        }
    }

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    At least that works for me with your test case.  Not sure about the else "XXX Not tested" branch, though... (probably still wrong, because I suppose the ->fdopen() would fail as well (just like ->opened), in case $self->io_handle is undefined).

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Re: How do I create an IO::All object from a pre-existing filehandle
by ikegami (Patriarch) on Jun 11, 2009 at 18:50 UTC
    GIGO. An IO::File object is not a valid argument. "Only" the following are acceptable:
    • A file name
    • A file handle
    • A directory name
    • A directory handle
    • A typeglob reference
    • A piped shell command. eq '| ls -al'
    • A socket domain/port. eg 'perl.com:5678'
    • '-' means STDIN or STDOUT (depending on usage)
    • '=' means STDERR
    • '$' means an IO::String object
    • '?' means a temporary file
    • A URI including: http, https, ftp and mailto
    • An IO::All object

    Update: Then again, passing *G or \*G doesn't work either. And neither does io->handle($h). And it's not specific to Windows.

    Looks like a bug.

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Re: How do I create an IO::All object from a pre-existing filehandle
by Anonymous Monk on Jun 11, 2009 at 00:39 UTC
    IO:All v0.33)

    Try upgrading

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      I suppose I could, but I've reviewed the release notes for version 0.34 to 0.39 (latest) and none lists any changes that would be relevant, so I doubt an upgrade would be useful in this case.

      --DrWhy

      "If God had meant for us to think for ourselves he would have given us brains. Oh, wait..."

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        so I doubt an upgrade would be useful in this case.

        Do it anyway.

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