If the object file is newer than the assembly file, it will not re-assemble. The use of make files simplifies the re-assembly by only assembling those files which have been modified. It keeps a record of all the changes made to the program. An Object code library contains routines which can be reused in any program. The code for the routine is extracted from the library and combined with the users object code at linking time.
Users can create their own library routines.
The source files are assembled into object code then added to a library. The following code represents a routine for placement into a Video routines library. After assembling into Object code, the object code is placed into a video library using the TLIB utility. The following source file shows how to use the code in a library. These cannot be executed directly on the computer system, but require further processing in order to generate a runfile.