Programming considerations

For exit point MSOXITA (R0=0) your exit routine has the option to return a return code that allows the user to specify that the signon should be rejected. A return code of 12 or 16 indicates that normal HASPBSC signon processing can be bypassed. In this case your installation exit routine is responsible for performing all the necessary syntax processing that HASPBSC does and for returning a valid RAT entry pointer in R0.
For the signoff exit point your exit routine should return a return code of 0 or 4 so that normal processing can continue.
To define and implement an installation-defined remote name, change the remote name to a standard JES2 remote name on the signon card and return with a return code of 0, or supply a valid RAT pointer (valid for the installation-defined remote name) and return with or return code of 12 or 16.
Your installation exit routine should not issue a $WAIT or invoke a service routine that issues a $WAIT.
For the syntax of the signon card, see z/OS JES2 Initialization and Tuning Guide.
The $RETURN macro destroys the contents of register 0. Therefore, if you return the RAT address in R0, be certain to have provided a $STORE R0 instruction before the $RETURN to place the contents of R0 in the current save area before return to JES2.