/* if there's a port with a ready buffer, don't block, just
check for ready file descriptors. */
- if (!SCM_NULLP (read_ports_ready) || !SCM_NULLP (write_ports_ready))
+ if (!scm_is_null (read_ports_ready) || !scm_is_null (write_ports_ready))
{
timeout.tv_sec = 0;
timeout.tv_usec = 0;