Don't ask to ask, just ask. Post the code here which you're having problems with and you'll be much more likely to get help. See also How (Not) To Ask A Question.

I think you misunderstood my request. I was referring to the code in Mail::Message for 'get'. Do you really want me to post all that source? My code is essentially the one line call in the subject field.

No, you need to post a trimmed down relevant sample that shows the same behavior. Maybe you've got a missing letter in a variable name and aren't using strict so it's not getting caught. Maybe you've neglected to append a newline to a print and you're suffering from buffering. Maybe you've called something that's causing a real problem down inside Mail::Message. No one here can diagnose that because you haven't shown the code that's not working. You've given no details, just a vague "something resembling this snippet of code in some context at some time isn't working for me".

Not that it's inconceivable that there's a problem with the module in question, but no one's going to be able to divine what might be going wrong without any actual real code exhibiting the behavior in question to paw over and figure out what might be going wrong.

Update: Something like this (which by the way works fine for me; sample output after the __END__):

#!/usr/local/bin/perl5.10.0
use strict;
use warnings;
use feature ':5.10';

use Mail::Box::Manager;

my $mgr = Mail::Box::Manager->new();

my $folder = $mgr->open( "$ENV{HOME}/Mail/outgoing" );

my $msg = $folder->message( 0 );

for my $header ( qw( subject from received bogus ) ) {
  say "Msg $header: ", $msg->get( $header ) // 'UNDEF';
}

exit 0;

__END__
Msg subject: testing comp
Msg from: Mike Fletcher <REDACTED>
Msg received: UNDEF
Msg bogus: UNDEF
[download]

That's actual code that someone can grab, tweak the path to a mailbox for their environment, and attempt to duplicate your problem. It shows exactly what is being done when things don't behave (or are behaving as it does in this case since that message has no "Received" headers). Ideally you'd even include a sample message/mbox file which includes a "Received" header but the same code doesn't print it out (but that might be getting greedy :).

The cake is a lie.
The cake is a lie.
The cake is a lie.

Could this be relevant, from the documentation:

$obj->get(FIELDNAME)

Returns the value which is stored in the header field with the specified name. The FIELDNAME is case insensitive. The unfolded body of the field is returned, stripped from any attributes. See Mail::Message::Field::body().

If the field has multiple appearances in the header, only the last instance is returned. If you need more complex handing of fields, then call Mail::Message::Head::get() yourself. See study() when you want to be smart, doing the better (but slower) job.

I note that the field name is case insensitive, so it's not that. While this says that $msg->get('Received') will only receive the last if there are many, it doesn't quite explain why you get none at all. But I note the reference to Mail::Message::Head::get(). I also found:

  my @rec  = $msg->head->study('Received');
[download]