rlm_perl CLONE under freeradius 3.x

[d tbsky]

hi:
    I am writing rlm_perl script under freeradius 3.0.4 which comes
with RHEL 7.1.
and I am confused about how thread working with rlm_perl.
according to the old message at email list, if I want every radius
thread  to have their own unique variable, I should put the variable
at "CLONE" function like below:

our ($var);
CLONE {
   $var = '';
}

but after testing, I found even if the variable is not put at the
CLONE function, they are still unique to each thread. may I ask what
is the correct method to make global thread shared variable and thread
unique variable under rlm_perl ?

Regards,
tbskyd