Note: IBM® recommends
the use of stacking PC routines instead of basic PC routines; stacking
PC routines use system-provided linkage rather than issuing PCLINK
to save and restore the caller's environment.
Routines that receive control as a result of a basic PC instruction
use the PCLINK macro to provide a standardized method of maintaining
basic PC linkage information. PCLINK has three forms:
- PCLINK STACK saves some of the environment when a routine gets
control as a result of a basic PC instruction.
- PCLINK UNSTACK restores that environment before the routine issues
a PT instruction to return control to the calling routine.
- PCLINK EXTRACT retrieves information from the environment that
PCLINK STACK saved.
See z/OS MVS Programming: Extended Addressability Guide for
information about basic and stacking PC routines, the instructions
they can use, and the environmental information that PCLINK saves
and restores.