Beefy Boxes and Bandwidth Generously Provided by pair Networks
Just another Perl shrine

Answer: Subroutine args by-value vs. by-ref

( #192525=categorized answer: print w/ replies, xml ) Need Help??

Q&A > subroutines > Subroutine args by-value vs. by-ref contributed by wog

The implict reference is not a hard reference, as perlref speaks of, but an aliasing that occurs. For example:

sub x { $_[0] = "in x"; } my $foo = "outside"; x($foo);
... will set $foo to "in x". The thing in @_ has become an alias for $foo. However, you won't get this behavior if you explictly copy the value out of @_, as in:
sub x { my($foo) = @_; $foo = "in x"; } my $foo = "outside"; x($foo);
When you copy the value, you are not working with an alias to the thing passed in, but you a working with a copy, bringing you the pass-by-value semantics that are probably more intutitive to you.

Comment on Answer: Subroutine args by-value vs. by-ref
Select or Download Code
Log In?

What's my password?
Create A New User
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others chanting in the Monastery: (15)
As of 2015-11-30 16:52 GMT
Find Nodes?
    Voting Booth?

    What would be the most significant thing to happen if a rope (or wire) tied the Earth and the Moon together?

    Results (777 votes), past polls