Mr Valery,
thanks for the reply,and i have one more doubt when i upload file ,name ,content-type ,path of that file will be stored in upload_set_form_field ($upload_file_name,$upload_file_type,$upload_tmp_path).can i print this variable in log file.can i use
seperate log file for to print this variable.if it is possible how can i do that? .because there is default access log in nginx and i tried to print variable in seperate log file but it is printing that default access log .

thanks for the reply