gtpi1m0a | System Installation Support Reference |
The CCUEXT CSECT contains user-written exit routines and associated TPF control mechanisms. Therefore, you do not have to update the TPF control program in many locations to apply user-written code.
CCUEXT contains the following major functional components:
The UCL and its DSECT are generated by the DCTUCL macro. The UCL is allocated and initialized in CCUEXT. The UCL contains the following information for each exit point:
The current address is the same as the default address unless changed by the UXCMC macro. The default address is defined by address constants using specific user exit routine labels in copy member CUSR. The UCL is addressable in the control program (by referencing the label UCLTAB), from the control program itself, or from an E-type program (by CINFC for label CMMUCL).
The entry point of the UXCMC service routine is CPMUXT. The input to UXCMC is the UX1PL DSECT parameter list. UX1PL is formatted by the caller. UX1PL designates the type of action to be taken (activate or deactivate), the exit points to be acted on, and functions in the exit to be acted on. For activate, UX1PL can designate functions to be activated and the address of the alternate user processing routine for exit points.
For deactivate, UX1PL can designate functions to be deactivated.
If UX1PL is formatted correctly, the requested action is taken. If UX1PL is not formatted correctly, you receive an appropriate return code and no action is taken.
The General Post-Interrupt Routine (UXGPIR) allows you to restart user-suspended ECBs. The ADDLC or ADDFC macro, with a post-interrupt address of UXPI (a routine in CCNUCL), places an ECB on a dispatch list. When the ECB is removed from the list, by the System Task Dispatcher (CPU Loop), UXPI passes control to UXGPIR. If the post-interrupt exit point is active, UXGPIR passes control to the user's post-interrupt exit routine. If the post-interrupt exit point is not active, the suspended ECB is reactivated by executing a load PSW from the PSW in the ECB field CE1PSW.
User exit routines are user developed code to be processed at each active exit point.
User IDOTB macro calls associate one or more areas of main storage with a given system error. Use of the static override bitmap table and its effect on dump content are described in the TPF Program Development Support Reference.