Signal handling in openUTM

When a signal occurs, the following actions are possible:

• The signal is ignored (see table).

• If the signal occurs while program components created by the user are running:A PEND ER with KCRCC=70Z and KCRCDC=XTxx is called (xx is the signal number). The affected service or work process is terminated.

  Exception: If a registered user signal routine is existing on a Unix or Linux system, then this routine is called instead of that. Please refer to the openUTM manual „Programming Applications with KDCS” for details.

• If the signal occurs while the UTM system components are running:
  The application is terminated abnormally with REASON=SIGxxx (xxx is the signal number).

The table below shows the reaction of a work process to the individual signals. Detailed information on signals can be found in the C header file for signals (signal.h).

Signal received	Reaction
SIGHUP	ignored
SIGINT	ignored
SIGQUIT	ignored
SIGILL	PEND ER/TRMA1
SIGTRAP	ignored
SIGABRT	ignored
SIGEMT	ignored
SIGFPE	PEND ER/TRMA1
SIGBUS	PEND ER/TRMA1
SIGSEGV	PEND ER/TRMA1
SIGSYS	PEND ER/TRMA1
SIGPIPE	ignored
SIGALRM	PEND ER2/ ignored
SIGTERM	ignored
SIGUSR1	ignored
SIGUSR2	ignored
SIGCHLD	ignored
SIGPWR	PEND ER/TRMA1
SIGWINCH	ignored
SIGURG	ignored
SIGIO	ignored
SIGTSTP	ignored
SIGCONT	ignored
SIGTTIN	ignored
SIGTTOU	ignored
SIGVTALRM	ignored
SIGPROF	ignored
SIGXCPU	PEND ER/TRMA1
SIGXFSZ	PEND ER/TRMA1

¹TRMA stands for Term Application (= terminate application)

²PEND ER if timer is activated (KDCDEF generation TAC RTIME=<rtime>)

If the termination handling caused by the signal is interrupted by the arrival of another signal, this signal is not intercepted by openUTM. In this case, the operating system takes over the handling of the signal interrupt.

Signals in user signal routine

If another signal occurs during the user signal routine, the standard handling of the operating system is activated for this signal. This leads to an abnormal termination of the UTM application.