tac_process don't work !!


I tried to get xml format data to database direct using tac_process command. Database returns error message: data not valid.
If I save same information form buffer to disc and use tac_process_from_file there is no problem. This xml-file is also valid if I use interactive interface and load file to database. I like to get some example code how to use tac_process command. Another problem is how to update data to database using tamino API4C.