How to create a custom exception for the use of CURRVAL on sequences.

define_exception_for_currval.sql

Declare
  nextvalnotfound Exception;
  Pragma Exception_Init(nextvalnotfound, -08002);
  lc_secuencia Number;
Begin
  SELECT sfps010s.currval INTO lc_secuencia FROM dual;
Exception
  When nextvalnotfound Then
    dbms_output.put_line('NextVal is not found it!');
  When Others Then
    dbms_output.put_line('Error: ' || Sqlerrm);
End;