$ makeOn AIX it looks like the signal handler doesn't get the expected signal in the second argument (siginfo_t*) if the signal handler is installed with SA_RESETHANDLER.
$ ./signals
raise SIGUSR1 signal
signo 30 si_signo 0 si_code 0
$Expect the si_signo field of the second argument to be equal to the first argument.
$ ./signals
raise SIGUSR1 signal
signo 30 si_signo 30 si_code 0
$$ ./signals
raise SIGUSR1 signal
signo 10 si_signo 10 si_code 0
$>./signals
raise SIGUSR1 signal
signo 16 si_signo 16 si_code 0
>