SQL Anywhere does not provide a built-in prefilter algorithm. To have data pass through an external prefilter library, you specify the library and its entry point function using the ALTER TEXT CONFIGURATION statement, similar to the following:

ALTER TEXT CONFIGURATION my_text_config 
   PREFILTER EXTERNAL NAME 'my_prefilter@myprefilterLibrary.dll'

This example tells the database server to use the my_prefilter entry point function in the myprefilterLibrary.dll library to obtain a prefilter instance to use when building or updating a text index using the my_text_config text configuration object. The interface for a prefilter is described here: a_text_source interface.

See also: ALTER TEXT CONFIGURATION statement.