tryit "&Internals::SvREADONLY($arg)";
tryit "&Internals::SvREFCNT($arg)";
tryit "&Internals::hv_clear_placeholders($arg)";
-tryit "&Internals::HvREHASH($arg)";
----
Usage: Internals::SvREADONLY(SCALAR[, ON]) at (eval 1) line 1.
Usage: Internals::SvREFCNT(SCALAR[, REFCOUNT]) at (eval 2) line 1.
Usage: Internals::hv_clear_placeholders(hv) at (eval 3) line 1.
-Internals::HvREHASH $hashref at (eval 4) line 1.
====
}