use strict;
use warnings;

our $limit =1050;

our $l=0;

sub tst {
    $l++;
    #warn "level: $l" unless $l%50;
    die "LIMIT $limit reached" if $l>$limit;
    tst();
}

tst();

##</code><code>##

D:\tmp\pm>perl -d tst_recursion.pl

Loading DB routines from perl5db.pl version 1.57
Editor support available.

Enter h or 'h h' for help, or 'perldoc perldebug' for more help.

main::(tst_recursion.pl:4):     our $limit =1050;

  DB<1> c
main::tst(tst_recursion.pl:9):      $l++;
1000 levels deep in subroutine calls!

  DB<1>

##</code><code>##

D:\tmp\pm>perl tst_recursion.pl
Deep recursion on subroutine "main::tst" at tst_recursion.pl line 12.
LIMIT 1050 reached at tst_recursion.pl line 11.

D:\tmp\pm>