Possible uses

A user may use a line number within a statement to pass control to another part of the data set. For example, a user may pass control to line number 200 using the statement GOTO 200. The RENUM, MOVE, and COPY subcommand processors do not handle line references that are within a statement; that is, they do not change the GOTO statement. If the line numbering is changed and line 200 becomes line 250, the GOTO statement will pass control to an incorrect statement (line 200 instead of line 250). You can write an exit that adjusts the line references within statements, as needed, whenever a terminal user issues RENUM, MOVE, or COPY.
Your exit can flag a statement based on some condition. One way of flagging a particular statement is to add a comment at the end of the statement.
RENUM, MOVE, and COPY renumber the line numbers in a data set based on either a default increment value or a value that the user specifies on the subcommand. You can use the exit to establish a different numbering scheme. For a description of how each of the subcommands handles line numbering, see .