As LanX suggests the ; separates mandatory arguments from optional arguments. The * is pretty much a "match any argument type". The probable intent of the prototype is to ensure that the sub is normally called with at least one argument and may be called with somewhat over 80 arguments.

That looks pretty nasty to my eye. I'd be inclined to get rid of the prototype and add a runtime check that does a decent job of validating the arguments. Along with a decent set of unit tests that would provide easier to understand code, better documentation (the unit tests show expected usage for the sub) and much better regression testing over the long haul.

Thank you for the additional insight into a probable why there are many asterisks after the semicolon.

* means only type globs allowed (# hmm ... only partly correct, see below)

; means here everything following the first argument is optional.

edit

A * allows the subroutine to accept a bareword, constant, scalar expression, typeglob, or a reference to a typeglob in that slot. The value will be available to the subroutine either as a simple scalar, or (in the latter two cases) as a reference to the typeglob.

...

A semicolon (; ) separates mandatory arguments from optional arguments. It is redundant before @ or % , which gobble up everything else.

Thanks for this. I should have read a bit more first before submitting this.

Hello AlienResidents, and welcome to the Monastery!

As LanX and GrandFather have explained, the given prototype has the effect of requiring one argument and allowing up to 82 additional arguments.

But it has another effect: it coerces each argument into scalar context. To demonstrate this, here is a script which takes advantage of the fact that calling a subroutine with an initial ampersand — &name(...) — disables the prototype for that function call. So does calling the subroutine via a reference:

#! perl
use strict;
use warnings;

sub name(*;**)
{
    printf "First  argument: %s\n" .
           "Second argument: %s\n" .
           "Third  argument: %s\n\n", @_;
}

printf "\nname() has prototype (%s)\n\n", prototype('name');
my @array = ('foo', 'bar');
&name('1a',  'u', 'v');
 name('1b',  'u', 'v');
&name('2a', ('x', 'y'));
 name('2b', ('x', 'y'));
&name('3a', @array, 'extra_1');
 name('3b', @array, 'extra_2');
my $fp = \&name;
$fp->('3c', @array, 'extra_3');
[download]

Output:

See Far More than Everything You've Ever Wanted to Know about Prototypes in Perl -- by Tom Christiansen.

Hope that helps,

So uhh, moments after I submitted this, I found the prototypes section in perlsub. Everything after a semicolon is optional.

Sorry for a question that is clearly explained in the perldocs.