Signal catch or ignore interrupts #include <signal.h> typedef int (*sighandler_t)(int); sighandler_t signal int interrupt sighandler_t address This call is a comprehensive method of catching or ignoring signals sent to the current process. Notice that "kill()" does the sending of signals, and "signal()" does the catching. The signals used by OS-9 are defined in the header file as follows: /* OS-9 signals */ #define SIGKILL 0 /* system abort (cannot be caught or ignored)*/ #define SIGWAKE 1 /* wake up */ #define SIGQUIT 2 /* keyboard abort */ #define SIGINT 3 /* keyboard interrupt */ /* special addresses */ #define SIG_DFL 0 /* reset to default */ #define SIG_IGN 1 /* ignore */ Please note that there is another method of trapping signals, namely "intercept()" (q.v.). However, since "signal()" and "intercept()" are mutually incompatible, calls to both of them must not appear in the same program. The link-loader will preven the creation of an executable program in which both are called by aborting with an "entry name clash" error for "_sigint". intercept(), OS-9 shell command "kill", kill()