Example

Suppose the user has his additive model routine in the file USER1.FOR in USRDISK:[RONTGEN.XSPEC].

$ set def usrdisk:[rontgen.xspec]        ! Change directory.

$ fortran user1                          ! Compile.

$ mkumd user1                            ! Link the executable.

$ setumd user1                           ! Set logical umdshr.

$ xspec                                  ! Start xspec.

XSPEC> model wabs useradd1            ! Define model.