in reply to prototypes for dual-file handle print?

There's no way to define a sub to have the same syntax as print, much less a version with an extra handle.

It is possible to create a handle that writes to two other handles, though. See IO::Tee

how is the "die" function prototyped?

Use prototype to determine that. 

$ perl -wle'print prototype("CORE::die")'
@

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But also see $SIG{__DIE__} in perlvar.

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Re^2: prototypes for dual-file handle print?
by Anonymous Monk on Jul 06, 2010 at 08:14 UTC
    There's no way to define a sub to have the same syntax as print

    I always thought function $foo $bar is another notation for $foo->function($bar) (which is also often used to imitate the new operator from other languages). So for example the following works: 

    use warnings;
use strict;

my $mp = MyPrint->new(*STDERR);

$mp->myprint("foobar\n");
myprint $mp "foobar\n";

package MyPrint;

sub new {
    my ($class, $out) = @_;
    return bless { out => $out }, $class;
}

sub myprint {
    my ($self, $text) = @_;
    my $out = $self->{out};
    print $out $text;
}

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    I don't really know why STDERR->print "foobar" doesn't work though. It dies with 

    Can't locate object method "print" via package "IO::Handle"

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    although the documentation says something else.
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      I always thought function $foo $bar is another notation for $foo->function($bar)

      Ah yes. Indirect method call. It can cause headaches, so I don't use it. If a function or op with the same name as the method exists in the current namespace, it's not parsed as an indirect method call. Since print is an op, print $obj ... will never be an indirect method call, and it can't be used to solve the OP's problem.

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      $ perl -le 'use IO::Handle();STDOUT->print( qq{A "use IO::Handle" help
+s immensely} );' 
A "use IO::Handle" helps immensely

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

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