+extern int serial_debug_p (struct serial *scb);
+
+
+/* Details of an instance of a serial object */
+
+struct serial
+ {
+ int fd; /* File descriptor */
+ struct serial_ops *ops; /* Function vector */
+ void *state; /* Local context info for open FD */
+ serial_ttystate ttystate; /* Not used (yet) */
+ int bufcnt; /* Amount of data remaining in receive
+ buffer. -ve for sticky errors. */
+ unsigned char *bufp; /* Current byte */
+ unsigned char buf[BUFSIZ]; /* Da buffer itself */
+ int current_timeout; /* (ser-unix.c termio{,s} only), last
+ value of VTIME */
+ int timeout_remaining; /* (ser-unix.c termio{,s} only), we
+ still need to wait for this many
+ more seconds. */
+ char *name; /* The name of the device or host */
+ struct serial *next; /* Pointer to the next `struct serial *' */
+ int refcnt; /* Number of pointers to this block */
+ int debug_p; /* Trace this serial devices operation. */
+ int async_state; /* Async internal state. */
+ void *async_context; /* Async event thread's context */
+ serial_event_ftype *async_handler;/* Async event handler */
+ };
+
+struct serial_ops
+ {
+ char *name;
+ struct serial_ops *next;
+ int (*open) (struct serial *, const char *name);
+ void (*close) (struct serial *);
+ int (*readchar) (struct serial *, int timeout);
+ int (*write) (struct serial *, const char *str, int len);
+ /* Discard pending output */
+ int (*flush_output) (struct serial *);
+ /* Discard pending input */
+ int (*flush_input) (struct serial *);
+ int (*send_break) (struct serial *);
+ void (*go_raw) (struct serial *);
+ serial_ttystate (*get_tty_state) (struct serial *);
+ int (*set_tty_state) (struct serial *, serial_ttystate);
+ void (*print_tty_state) (struct serial *, serial_ttystate,
+ struct ui_file *);
+ int (*noflush_set_tty_state) (struct serial *, serial_ttystate,
+ serial_ttystate);
+ int (*setbaudrate) (struct serial *, int rate);
+ int (*setstopbits) (struct serial *, int num);
+ /* Wait for output to drain */
+ int (*drain_output) (struct serial *);
+ /* Change the serial device into/out of asynchronous mode, call
+ the specified function when ever there is something
+ interesting. */
+ void (*async) (struct serial *scb, int async_p);
+ };
+
+/* Add a new serial interface to the interface list */