nset              163 src/popen.c    	sigset_t oset, nset;
nset              175 src/popen.c    	sigemptyset(&nset);
nset              176 src/popen.c    	sigaddset(&nset, SIGINT);
nset              177 src/popen.c    	sigaddset(&nset, SIGQUIT);
nset              178 src/popen.c    	sigaddset(&nset, SIGHUP);
nset              179 src/popen.c    	(void) sigprocmask(SIG_BLOCK, &nset, &oset);