Ruby

ruby_signal() in signal.c returns old.sa_handler,
but it should return either old.sa_sigaction or old.sa_handler,
depending on whether SA_SIGINFO is set in old.sa_flags.

--- signal.c (revision 46222) +++ signal.c (working copy) @@ -595,7 +595,10 @@ rb_bug_errno("sigaction", errno); } } - return old.sa_handler; + if (old.sa_flags & SA_SIGINFO) + return (sighandler_t)old.sa_sigaction; + else + return old.sa_handler;  } sighandler_t 

The original code happens to be correct on the environments
where sa_handler and sa_sigaction are union, but it is not
guaranteed in general.

(Actually, they are not union on z/OS.)