CHECKn
CHECKn(ttynm = ttyname(STDOUT_FILENO));
CHECKn(printf("This output is necessary to set the stdout fd to NONBLOCKING\n"));
CHECKn(execve(bad_argv[0], bad_argv, environ));
CHECKn(pw = getpwuid(getuid()));
CHECKn(dot_dir = opendir("."));
CHECKn(slpr = popen("sleep 2; echo foo", "r"));
CHECKn(sem_destroy(&cons_sem));
CHECKn(sem_timedwait(&sem, &ts));
CHECKn(sem_destroy(&sem));
CHECKn(sem_timedwait(&sem, &ts));
CHECKn(sem_trywait(&sem));
CHECKn(sem_trywait(&sem));
CHECKn(sem_wait(&sem));
CHECKn(sem_destroy(&sem));
CHECKn(fullname = malloc (len));
CHECKn((fp = fopen(fullname, "r")));
CHECKn(fp1 = fopen(fullname, "r"));
CHECKn(fp2 = fopen(fullname, "r"));