Function FD_SET

Kernel/include/fs/filesystem.h:136–139

	return fds->fds_bits[fd / 8] & (1 << (fd % 8));
}
static inline void FD_SET(int fd, fd_set_t* fds) {
	assert(fd < FD_SETSIZE);
	fds->fds_bits[fd / 8] |= 1 << (fd % 8);
}
static inline void FD_ZERO(fd_set_t* fds) {
	memset(fds, 0, sizeof(fd_set_t));
}