High-level-language signal interfaces

In addition to the signal interface callable services that are defined by POSIX, z/OS UNIX provides the following signal interface services:

mvssigsetup service: Sets up and defines the signal interface routine (SIR). The SIR is a routine that is provided by the high-level language. For information about how to write the SIR and the interface to it, see mvssigsetup (BPX1MSS, BPX4MSS) — Set up MVS signals.
mvsunsigsetup service: Detaches the interface to the SIR and returns the parameters set up in mvssigsetup. See mvsunsigsetup (BPX1MSD, BPX4MSD) — Detach the signal setup.
ptrace service: Controls the running of another process for debugging programs. See ptrace (BPX1PTR, BPX4PTR) — Control another process for debugging.
queue_interrupt service: Returns the last signal delivered. See queue_interrupt (BPX1SPB, BPX4SPB) — Return the last interrupt delivered.

These interfaces allow a runtime library (RTL) for a high-level language to control the flow of signals. Each high-level language defines its own linkage interface between callable procedures; for example, the C language has a linkage stack and register interface between function procedures, which are unique to C.

Delivery of signals involves:

Interrupting a currently running procedure
Saving the status of the code that was interrupted
Invoking a callable procedure known as the signal catcher, or signal handler.