wait_for_single_fd    5 ext/-test-/wait_for_single_fd/wait_for_single_fd.c wait_for_single_fd(VALUE ign, VALUE fd, VALUE events, VALUE timeout)
wait_for_single_fd   62 ext/io/wait/wait.c wait_for_single_fd(rb_io_t *fptr, int events, struct timeval *tv)