Can you tell what $$$\@ means?

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

Just curious, but what does this mean? I was browsing some code from sourceforge and came across a function that starts like this


sub extract_seed_page($$$\@){
  my ($filepath, $keyword, $percent, $phrase_list_ref) = @_;
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Re: Can you tell what $$$\@ means? by kyle (Abbot) on Apr 27, 2008 at 04:07 UTC
It's a prototype. It's documented in perlsub under Prototypes. In this case, the prototype says that the function expects to get three scalars and a reference to an array. See also: Are prototypes evil? subroutine prototypes still bad? Gratuitous use of Perl Prototypes	[reply]
Re^2: Can you tell what $$$\@ means? by crusty_collins (Friar) on Apr 27, 2008 at 04:13 UTC
Thanks for that. I guess now I will do some reading on prototypes.	[reply]
Re^3: Can you tell what $$$\@ means? by GrandFather (Saint) on Apr 27, 2008 at 08:48 UTC
Read just enough to recognize them when you see em. Prototypes are one of the corners of Perl that tend to be left unused for the most part because they tend toward surprising behavior. Perl is environmentally friendly - it saves trees	[reply]
Re^4: Can you tell what $$$\@ means? by sasdrtx (Friar) on Apr 27, 2008 at 13:20 UTC
Re^5: Can you tell what $$$\@ means? by Fletch (Bishop) on Apr 27, 2008 at 14:18 UTC
Re^5: Can you tell what $$$\@ means? by GrandFather (Saint) on Apr 27, 2008 at 21:05 UTC
Some notes below your chosen depth have not been shown here
Re: Can you tell what $$$\@ means? by GrandFather (Saint) on Apr 27, 2008 at 04:02 UTC
It's a sub with a prototype. The prototype specifies that the sub takes three scalar parameters and a reference to an array. Perl is environmentally friendly - it saves trees	[reply]