does it secures script

Yes it does. :)

can u help me
while i used
php_value auto_prepend_file filename.php
in .htaccess

my site showed an error :

Warning: Unknown: failed to open stream: No such file or directory in Unknown on line 0

Warning: Unknown: failed to open stream: No such file or directory in Unknown on line 0

Fatal error: Unknown: Failed opening required 'filename.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in Unknown on line 0

where's the error

Mahesh, you must use absolute path of filename.php for this. Do it like this:

php_value auto_prepend_file /home///filename.php

Also in case .htaccess directive is ignored, you can edit httpd.conf file to do the same or manually prepend the file in each and every php file.

how to use this sanitize function and where please ellaborate