cowrefcnt

How many scalars share a copy-on-write buffer, as perl counts.

Synopsis

use B::COW qw(cowrefcnt);
my $n = cowrefcnt($string);

What you get back

The share count perl keeps in the last byte of the buffer, 0 for a string that shares a hash key’s buffer (those have no count), or undef when the value is not copy-on-write.