root@raspberry2:/home/helmut# time perl -MConfig -E 'print $Config{ivsize};'
8
real	0m0.177s
user	0m0.160s
sys	0m0.010s
root@raspberry2:/home/helmut# time perl -e  'print length(pack('j', -1))*8;'
64
real	0m0.028s
user	0m0.020s
sys	0m0.000s