note vitoco <p>As [ikegami] said, <c>sub</c>s are global:</p> <code> #!perl use v5.10; use strict; use warnings; my $a = shift; sub f { say "global f"; } sub g { say "global g"; my ($a) = @_; sub f { say "local f ($a)"; # line 16 } f(); } f(); g(shift); f(); __END__ C:\Temp>localsub.pl Variable "$a" will not stay shared at C:\Temp\localsub.pl line 16. Subroutine f redefined at C:\Temp\localsub.pl line 15. Use of uninitialized value $a in concatenation (.) or string at C:\Temp\localsub.pl line 16. local f () global g Use of uninitialized value $a in concatenation (.) or string at C:\Temp\localsub.pl line 16. local f () Use of uninitialized value $a in concatenation (.) or string at C:\Temp\localsub.pl line 16. local f () C:\Temp>localsub.pl AAA BBB Variable "$a" will not stay shared at C:\Temp\localsub.pl line 16. Subroutine f redefined at C:\Temp\localsub.pl line 15. Use of uninitialized value $a in concatenation (.) or string at C:\Temp\localsub.pl line 16. local f () global g local f (BBB) local f (BBB) </code> <p>What is a strange behavior is that variables got stuck with a value, even if it is assigned after it's first use... That does not seem to be a compile time assignment.</p> <p>Conclusion: always define global subroutines or pass variables as parameters to them if defined locally for clarity.</p> 809000 809000