The exit must follow standard linkage conventions. It must save the registers on entry and restore the registers when it returns.

The exit can access the ECT and UPT to invoke the parse service routine or the TSO/E service routines. For information about the service routines, see .

Use the exit to fill in the option word for your syntax checker according to information the user enters. When users issue the EDIT command and specify your installation's data set type keyword, they can also specify a subfield. This subfield can contain any valid alphanumeric data defined. The data cannot exceed 256 characters and cannot contain any blanks, tabulation characters, or commas. The information is passed to the exit, which interprets it and encodes it into bytes 0 and 1 of the option word. For information about the standard interface between EDIT and syntax checkers and the option word, see Record format and interface for syntax checking.