C library functions (alarm, raise, signal)

The concept of contingency routines or STXIT contingency routines is primarily handled by the following C library functions:

alarm	sends the SIGALRM signal (STXIT event RTIMER)
raise	sends signals (simulated STXIT events and user-defined events)
signal	assigns signal handling routines

STXIT contingency routines

The following STXIT event classes can be processed by means of the alarm, raise and signal functions:

• PROCHK (program check)

• TIMER (CPU time interval timer)

• RUNOUT (end of program runtime)

• ERROR (unrecoverable program errors)

• INTR (information for the program)

• BREAK/ESCAPE (ESCPBRK) only in the dialog

• ABEND

• TERM (normal termination of program)

• RTIMER (real time interval timer)

The SVC interrupt event class is not supported at present.

Event-driven routines

The signal and raise functions can be used to implement two event-driven routines via two user-defined signals (SIGUSR1, SIGUSR2).

Eventing via C library functions only operates within a task, i.e. intercommunication between different tasks is not possible.
These event-driven routines are therefore not implemented internally as contingency routines but via a CALL interface.