The application programming interface USR0020P in the Natural system library SYSEXT is provided to read messages from the FNAT or FUSER system file. Thus, it is possible, for example, to have long messages displayed in an application (as part of your own user-defined help system) without having to use the Natural system library SYSERR.

Log on to the Natural system library SYSEXT and, in the command line, enter the command MENU. In the list provided, mark the program USR0020P with a question mark (?). A window is then displayed, in which you can select the function to be executed for the program. If you enter an I, further information on the use of USR0020P is displayed.