SvREFCNT is exposed in Devel::Peek (no need to go to CPAN), which is a bit easier to use than embedding XS. For example:
use Devel::Peek qw(SvREFCNT);

$x = 42;
$y = \$x;

$refs_for_x = SvREFCNT($x);
print "$refs_for_x\n";

[download]
Prints 2.

In reply to Re^2: The number of references to a variable by cdarke
in thread The number of references to a variable by jeanluca

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