Pass object to subroutine.

tacoking92 has asked for the wisdom of the Perl Monks concerning the following question:

Hi all, first post here. Hopefully someone can help me figure out my little problem I'm fighting with.

I'm attempting to pass an Net::OpenSSH object between subroutines and I'm finding it pretty difficult to do.

Here's what I'm trying.

my $ssh = login($user, $pass, $host);
test(\$ssh);

sub login  {
  ($user, $pass, $host) = @_;
  my $ssh = Net::OpenSSH -> new($host, user=>$user, password=> $pass);
  return $ssh;
}

sub test {
  $ssh2 = shift;
  $output = $ssh2 -> capture("ls /tmp");
  print $output;
}
[download]

I get the following error: "Can't call method "capture" on unblessed reference at ./test3.pl"

Is there a way I can pass the object reference between the subroutines?

Thanks for the help.

Comment on Pass object to subroutine. Download Code

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Re: Pass object to subroutine. by MidLifeXis (Monsignor) on Nov 15, 2011 at 19:01 UTC
`my $ssh = login($user, $pass, $host); test(\$ssh);` [download] `$ssh` is already a blessed reference. If you pass it to `test()` like `test(\$ssh)`, you are passing an unblessed reference to a blessed reference. You should pass it to `test` like `test($ssh)`. Update: See also ref bless perlref --MidLifeXis	[reply] [d/l] [select]
Re: Pass object to subroutine. by mrstlee (Beadle) on Nov 15, 2011 at 22:09 UTC
Try this to see the difference between $ssh & \$ssh: `use Data::Dumper; my $ssh = login($user, $pass, $host); print Dumper $ssh; print Dumper \$ssh;` [download] Objects in perl are often, but not always, references to a hash that has been "bless"ed into a particular namespace. In this case Net::OpenSSH->new returns a reference to a hash. In fact you can bless any reference - array refs, scalar refs, even sub-routine refs It's easy to create your own blessed references `use Data::Dumper; my $obj_ref = bless {} , 'Any::Old::Perl::Identifier'; sub Any::Old::Perl::Identifier::make_hay{ my ($self) = @_; $self->{'foo'} = 'hay'; } $obj_ref->make_hay(); print ref $obj_ref, "\n"; print ref \$obj_ref, "\n"; print Dumper $obj_ref;` [download] Prints: `Any::Old::Perl::Identifier REF $VAR1 = bless( { 'foo' => 'hay' }, 'Any::Old::Perl::Identifier' );` [download] You can see that the obj_ref has made hay. Refs can be a bit confusing. Try the perlreftut tutorial in the core perl documentation.	[reply] [d/l] [select]