SQL & PL/SQL

Hi There,

I had a varchar2 variable which was storing some data and I could use the LENGTH function to get the length of the data. However, If I change it to CLOB. What is the best way to get the length?
Online some suggestions are

v_clob_size:= (DBMS_LOB.getlength(v_clob)) / 1024 / 1024;
DBMS_OUTPUT.put_line('CLOB Size ' || v_clob_size);


another one is
LENGTHB(TO_CHAR(SUBSTR(<clob-column>,1,4000))) But this seems restricted to first 4000 characters only.

Thanks