Compilation error in a function due to simple IF-ELSEIF condition

Question

DB version:10gR2
I have created the below mentioned function to activate or deactivate a custom functionality in a package.
The functionlity should be activated only if the second byte of sys_config.flag_a ='Y' with CODE_ID='103'. If flag_a is null or if no such row exist , the function should return false
During the compilation, i am getting error as mentioned below. This can be easily reproduced.
create table sys_config (flag_a     varchar2(5), code_id varchar2(5));
create or replace function chk_if_mod_enabled
   return boolean
   is
      v_flag_a sys_config.flag_a%TYPE;
begin
     select nvl(substr(flag_a,2,1),'N')
     into v_flag_a
     from sys_config
     where     flag_a='Y'
     and     code_id='103';
     if     v_flag_a='Y'
          then return true;
     elseif     v_flag_a='N'
          then return false;
     else     return false;
     End If;
exception
when others
then
Return false;
end;The error i am getting is
Errors for FUNCTION CHK_IF_MOD_ENABLED:
LINE/COL ERROR
15/9     PLS-00103: Encountered the symbol "V_FLAG_A" when expecting one
         of the following:
         := . ( @ % ;
21/1     PLS-00103: Encountered the symbol "EXCEPTION" when expecting one
         of the following:
         begin case declare else elsif end exit for goto if loop mod
         null pragma raise return select update while with
         <an identifier> <a double-quoted delimited-identifier>
         <a bind variable> << close current delete fetch lock insert
         open rollback savepoint set sql execute commit forall merge
LINE/COL ERROR
         pipe
25/4     PLS-00103: Encountered the symbol "end-of-file" when expecting
         one of the following:
         end not pragma final instantiable order overriding static
         member constructor mapIf i comment out the ELSEIF bit from the code, i won't get any error. Why is this happening?

Answer 1

You are returning boolean type.
So, you should be careful about using this function. You cannot use that in SQL.
Regards.
Satyaki De.