133     fd_set read_fds, write_fds, error_fds;  variable
139     FD_ZERO(&write_fds);
142     int ret = select(fd + 1, &read_fds, &write_fds, &error_fds, &zero_time);
149     FD_ZERO(&write_fds);
152     ret = select(fd + 1, &read_fds, &write_fds, &error_fds, &zero_time);
158     FD_ZERO(&write_fds);
161     ret = select(fd + 1, &read_fds, &write_fds, &error_fds, &zero_time);
255     fd_set read_fds, write_fds, error_fds;  variable
257     FD_ZERO(&write_fds);
264     int ret = select(fd + 1, &read_fds, &write_fds, &error_fds, &wait_time);
290     fd_set read_fds, write_fds, error_fds;  variable
292     FD_ZERO(&write_fds);
299     int ret = select(fd + 1, &read_fds, &write_fds, &error_fds, &wait_time);