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

I have this script sends a report either to STDOUT or to an e-mail address via a library that is a subclass of Mail::Send.

What happens is that based on some command-line option, I am setting the variable $message to either *STDOUT or to $mail_obj->open() (Which returns a bless'ed glob of Mail::Mailer::smtp), I then select($message) and set $~ and $^ to the appropriate format names.

Anyway, when I try to write($message), the output seems to disappear when $message is the Mail::Mailer::smtp object, but when sent to STDOUT it works: e.g.

---- CODE BLOCK ----
{
    if($opt_mailto) {
    $mail_obj = VNI::Mailer->new();
    $mail_obj->to($opt_mailto);
    $mail_obj->subject($report_title);
    $mail_obj->from($from);

    $message = $mail_obj->open();
    } else {
    $message = *STDOUT;
    }

    # select whatever filehandle is in $message for output
    select($message);


# -- further down
    format MSG_TOP = 
blah some header for this report
---------------------------------
.

    format MSG =
@<<<<< @<<<<<< @<<<<<< @<<<<<<
$foo,  $bar,   $baz,   $quux
------------------------------
.

    $^ = "MSG_TOP";
    $~ = "MSG";

    foreach (@lusers) {
          $foo = $_->data; $bar =$_->otherdata; 
          # etc, etc,

          # THIS WRITE WORKS WHEN $message == *STDOUT
          # OUTPUT DISAPPEARS OTHERWISE
          write($message);
    }

    # The following prints always work correctly.
    print $message "Some summary info: $balance\n";
    print $message "People who suck: $sucky\n";
}

----- END CODE ----

[download]

So when I try doing this using the mail object, all I get is the summary information, but not the report itself.

Why? Why!?!?

This is perl 5.0005_4 on FreeBSD 4.4-STABLE

I tried a few different tricks and none of them worked, and one of the techniques actually caused perl to segfault!

I would think that write() is just a front-end for print(), so I don't know why print() would use the mail-filehandle correctly and write() not. Argh.

-bcd

Replies are listed 'Best First'.
Re: Formatted Output on glob-filehandles
by Thelonius (Priest) on Oct 24, 2002 at 20:10 UTC
    Have you tried write; without any arguments? Another thing you could try is $message->format_write(). I'm just guessing here, in case you couldn't tell.
[reply]
[d/l]
[select]
Re: Formatted Output on glob-filehandles
by Jenda (Abbot) on Oct 24, 2002 at 20:46 UTC

    From the code in Mail::Mailer I would expect a Mail::Mailer::smtp::pipe object anyway try to define the WRITE method like this: 

    { package Mail::Mailer::smtp::pipe;
 sub WRITE
 {
  my $fh = $_[0];
  print $fh substr($_[1],0,$_[2])
 }
}
# taken from Tie::Handle
or
{ package Mail::Mailer::smtp::pipe;
 sub WRITE
 {
  my $fh = $_[0];
  $fh->PRINT(substr($_[1],0,$_[2]))
 }
}
or maybe 
{ package Mail::Mailer::smtp::pipe;
 sub WRITE
 {
  my $fh = $_[0];
  $fh->format_write(substr($_[1],0,$_[2]))
 }
}

    [download]

    Of course if the glob really is Mail::Mailer::smtp define the function there :-)

    If this doesn't help (this is just a wild guess!) try to use Devel::TraceSubs to see what functions are called with what parameters.

    Jenda

[reply]
[d/l]

      Which are 5.6 modules, unfortunately.

      I tried adding those subs to the Mail::Mailer::smtp::pipe package (which the Mail::Mailer::smtp object is tied to), i added the rest of the missing filehandle TIE functions that just print some debugging, nada.

      I don't know..

[reply]
Re: Formatted Output on glob-filehandles
by VSarkiss (Monsignor) on Oct 24, 2002 at 19:51 UTC

    This is a shot in the dark, so take it with a grain of salt.

    Since you already have the output selected, don't pass it as a parameter to write. Quite possibly, it's being interpreted as an expression that holds a filehandle name rather than a filehandle. In other words, it may be trying to write to a filehandle named HASH(0xabcd) or some such. (That's the normal behaviour of write. Check out perlfunc:write.) If select has succeeded, then just call write with no parameter.

    HTH

[reply]
[d/l]
[select]

      Negatory. I had tried this before posting the message. I tried a few variations on this, like:

      # explicit file handle ($message)
write($message); 

# implicitly use selected output stream
write();

# Yah, I know this is wrong, but I had to try it.
write(MSG);

      [download]

      And as far as checking whether select() failed or not, I don't believe there is any way to do this (Please tell me I am wrong, because I can't accept that)

[reply]
[d/l]

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