lanx@lanx-1005HA:/tmp$ cat Weird.pm 
package Weird;

use Carp qw/cluck/;

sub tst {
    cluck "cluck tst entered";

    print "\nnormal output in tst()...\n";
    # ...
}

sub tst2 {
    tst();
}

warn "\n--- using Weird.pm\n";
tst2();                   # line 17 - executed at "use Weird" time


sub import {
    warn "\n--- importing from Weird.pm\n";
    tst2();               # line 22 - executed at Weird::import() time
}

1;

##</code><code>##

lanx@lanx-1005HA:/tmp$ cat t_carp.pl

warn "pre use\n";

use Weird;      # ab'use

warn "post use\n";

##</code><code>##

lanx@lanx-1005HA:/tmp$ perl -I. t_carp.pl

--- using Weird.pm
cluck tst entered at Weird.pm line 6
	Weird::tst() called at Weird.pm line 13
	Weird::tst2() called at Weird.pm line 17     <--- AHA !!!
	require Weird.pm called at t_carp.pl line 4
	main::BEGIN() called at Weird.pm line 0
	eval {...} called at Weird.pm line 0

normal output in tst()...

--- importing from Weird.pm
cluck tst entered at Weird.pm line 6
	Weird::tst() called at Weird.pm line 13
	Weird::tst2() called at Weird.pm line 22     <--- AHA !!!
	Weird::import('Weird') called at t_carp.pl line 4
	main::BEGIN() called at t_carp.pl line 4
	eval {...} called at t_carp.pl line 4

normal output in tst()...
pre use
post use