Knowing when it is safe to call currval() - Mailing list pgsql-sql

Hi All,

Is there any way to know ahead of time whether calling currval() on a 
sequence will cause an exception like:

ERROR:  some_id_seq.currval is not yet defined in this session

In my function I can't be sure whether nextval() will have previously 
been called in the session.

Thanks

Matthew.