SR_PRIV int serial_open(const char *pathname, int flags);
SR_PRIV int serial_close(int fd);
SR_PRIV int serial_flush(int fd);
SR_PRIV int serial_write(int fd, const void *buf, size_t count);
SR_PRIV int serial_read(int fd, void *buf, size_t count);
SR_PRIV int serial_open(const char *pathname, int flags);
SR_PRIV int serial_close(int fd);
SR_PRIV int serial_flush(int fd);
SR_PRIV int serial_write(int fd, const void *buf, size_t count);
SR_PRIV int serial_read(int fd, void *buf, size_t count);