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TICKIT_WATCH_IO(3)	    Library Functions Manual	      TICKIT_WATCH_IO(3)

NAME
     tickit_watch_io - invoke a callback when IO is possible

SYNOPSIS
     #include <tickit.h>

     typedef enum TickitIOCondition;

     typedef struct {
       int fd;
       TickitIOCondition cond;
     } TickitIOWatchInfo;

     typedef int TickitCallbackFn(Tickit *t, TickitEventflags flags,
	 void *info, void *user);

     void *tickit_watch_io(Tickit *t, int fd, TickitIOCondition cond,
	 TickitBindFlags flags, TickitCallbackFn *fn, void *user);

     Link with -ltickit.

DESCRIPTION
     tickit_watch_io()	registers  a  callback	function  to  be  invoked by the
     toplevel event loop when IO operations are possible on  a	given  file  de-
     scriptor.	A  registered  callback  will  be  invoked  by a running call to
     tickit_run(3). The callback function will be invoked whenever the file  de-
     scriptor is readable, writable, or in a hang-up condition, depending on the
     requested	condition types. The info pointer will point to a structure con-
     taining the file descriptor and a bitmask of the  IO  operations  currently
     possible.

     The  cond argument to tickit_watch_io() should be a bitmask of at least one
     of the following values:

     TICKIT_IO_IN
	    The file descriptor is ready to perform an input operation, such  as
	    reading bytes.

     TICKIT_IO_OUT
	    The file descriptor is ready to perform an output operation, such as
	    writing bytes.

     TICKIT_IO_PRI
	    The file descriptor has a high-priority condition to report.

     TICKIT_IO_HUP
	    The  file descriptor is in a hang-up condition. Typically this means
	    that a connection such as a socket or pipe has been  closed  by  the
	    peer.

     When  the	callback  function  is invoked, the info struct will contain the
     file descriptor in the fd field, and the current IO conditions in the  cond
     field.  This may be one of the values given above, and in addition may also
     be one of the following:

     TICKIT_IO_ERR
	    The file descriptor is in an error condition.

     TICKIT_IO_INVAL
	    The file descriptor itself is invalid and does not represent an open
	    file.

     If registered with the TICKIT_BIND_FIRST flag, the  callback  will  be  in-
     serted  at  the start of the queue, coming before others. If not, it is ap-
     pended at the end.

     If cancelled by tickit_watch_cancel(3) the  callback  function  is  invoked
     with  just  the  TICKIT_EV_UNBIND	flag  if  it  had  been  registered with
     TICKIT_BIND_UNBIND.

RETURN VALUE
     tickit_watch_io() returns an opaque identifier pointer.

SEE ALSO
     tickit_new_stdio(3),		       tickit_watch_timer_after_msec(3),
     tickit_watch_timer_at_epoch(3),   tickit_watch_later(3),  tickit_watch_sig-
     nal(3), tickit_watch_process(3), tickit_watch_cancel(3), tickit(7)

							      TICKIT_WATCH_IO(3)

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