sig_do_nothing   1079 signal.c               func = sig_do_nothing;
sig_do_nothing   1084 signal.c               func = sig_do_nothing;
sig_do_nothing   1500 signal.c           install_sighandler(SIGPIPE, sig_do_nothing);
sig_do_nothing   1503 signal.c           install_sighandler(SIGSYS, sig_do_nothing);