the datalog framework 200 includes a datalog stream interface 202 a datalog format interface 204 a datalog type interface 206 and a datalog source interface 208 the datalog framework 200 further includes a datalog manager class 210 a datalog format map class 212 a datalog format group class 214 a datalog values class 216 a general format class 218 and a user format class 220 the standard datalog interfaces to the tester operating system tos are defined as pure abstract c classes the datalog stream interface idatalogstream 202 represents an output file or device the datalog system sends formatted output to streams the system provides two built in streams a filestream for sending output to a local disk file and a consolestream for sending output to the system 39 s console application the datalog format interface idatalogformat 204 represents the necessary instructions required to format data associated with datalog events to an output the specific nature of the formatting capability is hidden inside each implementation of the idatalogformat for example the built in generalformat allows a general format string to be used with a macro like capability for extracting named values from the datalogvalues objects and inserting them into a formatted string the datalog type interface idatalogtype 206 represents a class or a u201c type u201d of datalog.