To_clob error

Question

Hi all,
I am facing an error when using the to_clob function.The usage returns a error:
SQL> declare
2 dtd clob;
3 begin
4 dtd:=TO_CLOB("asas");
5 end;
6 /
dtd:=TO_CLOB("asas");
ERROR at line 4:
ORA-06550: line 4, column 6:
PLS-00201: identifier 'TO_CLOB' must be declared
ORA-06550: line 4, column 1:
PL/SQL: Statement ignored
Here the block doesn't do anything but used for testing the to_clob function.Actually i am using this function somewhere else and try to find out the actual error ,i have used this.Considering this as an actual implementation can anyone tell me where i am wrong.
The PLS-00201 is identified as :-
PLS-00201 identifier 'string' must be declared
Cause: An attempt was made to reference either an undeclared variable, exception, procedure, or other item, or an item to which no privilege was granted or an item to which privilege was granted only through a role.
Action:
Check your spelling and declaration of the referenced name.
Verify that the declaration for the referenced item is placed correctly in the block structure.
If the referenced item is indeed declared but you do not have privileges to refer to that item, for security reasons, you will b[i]Long postings are being truncated to ~1 kB at this time.

Answer 1

Hi Peter,
The oracle version that i am using is
Oracle8i Enterprise Edition Release 8.1.7.0.0 (oracle 8i).
So now how is this conversion possible.You must have seen what i have been trying to do.I just want to convert or make a clob object out of a varchar data in my version.Can you please elaborate on this method.What package or identification unit provides this function is provided,how can i know that this function is not directly supported by this version.
With Regards
Gopal