SQL & PL/SQL

Hi all,


I want to know about the procedure fseek in utl_file
I know that we can use this procedure to move back or forward in a file without closing and opening it


but what i cant get is how this works

say this is the example

declare
 name varchar2(30);
 f1 utl_file.file_type;
 pos number; 
begin
   f1 := utl_file.fopen('VIR','SEARCH.TXT','R');
   utl_file.fseek(f1,10);
  	pos := utl_file.fgetpos(f1);
 dbms_output.put_line ('SUCCESS Seek to abs offset 10, currect position is '||to_char(pos));		
   utl_file.fseek(f1,NULL,5);
       pos := utl_file.fgetpos(f1);
 dbms_output.put_line ('SUCCESS Seek to relative offset 5, currect position is'||to_char(pos));
   utl_file.fseek(f1,10,5);
       pos := utl_file.fgetpos(f1);
 dbms_output.put_line ('SUCCESS Seek to absolute 10 relative offset 5, currect position is'||to_char(pos));
   utl_file.fseek(f1,NULL,-5);
       pos := utl_file.fgetpos(f1);
 dbms_output.put_line ('SUCCESS Seek to rel offset -5, currect position is '||to_char(pos));
   utl_file.fclose(f1);
end; 
/



o/p is




SQL> /
SUCCESS Seek to abs offset 10, currect position is 10
SUCCESS Seek to relative offset 5, currect position is15
SUCCESS Seek to absolute 10 relative offset 5, currect position is10
SUCCESS Seek to rel offset -5, currect position is 5

PL/SQL procedure successfully completed.

What i dont understand is when i am using both absolute and relative offset i.e abs = 10 and rel = 5
then why its current position is 10 when i thought it would be 15?
please correct me if i am wrong.

or does it not consider the relative offset when the absolute is given

What i am thinking is when absolute and relative offset in fseek is present then the position should be

absolute + relative.

when absolute is null and relative is present the position would be


current position +/- relative offset


and if relative offset is null and absolute is present the current position is

absolute offset


thanks