man(1) Manual page archive

     EVENT(2G)                                               EVENT(2G)

          event, einit, estart, etimer, eread, emouse, ekbd, ecanread,
          ecanmouse, ecankbd, ereshaped, getrect, menuhit, Event,
          Mouse, Menu - graphics events

          #include  <u.h>
          #include  <libc.h>
          #include  <libg.h>

          void      einit(ulong keys)

          ulong     event(Event *e)

          Mouse     emouse(void)

          int       ekbd(void)

          int       ecanmouse(void)

          int       ecankbd(void)

          ulong     estart(ulong key, int fd, int n)

          ulong     etimer(ulong key, int n)

          ulong     eread(ulong keys, Event *e)

          int       ecanread(ulong keys)

          void      ereshaped(Rectangle r)

          Rectangle getrect(int but, Mouse *m)

          int       menuhit(int but, Mouse *m, Menu *menu)

                    Emouse = 1,
                    Ekeyboard = 2,

          These routines provide an interface to multiple sources of
          input.  To use them, einit must be called.  If the argument
          to einit has the Emouse and Ekeyboard bits set, the mouse
          and keyboard events will be enabled; in this case, binit
          (see graphics(2)) must have already been called.  The user
          must provide a function called ereshaped to be called when-
          ever the window in which the process is running has been
          reshaped; the argument will be the Rectangle for the new

     EVENT(2G)                                               EVENT(2G)

          window shape, including the border.

          As characters are typed on the keyboard, they are read by
          the event mechanism and put in a queue.  Ekbd returns the
          next rune from the queue, blocking until the queue is non-
          empty.  The characters are read in raw mode (see cons(3)),
          so they are available as soon as a complete rune is typed.

          When the mouse moves or a mouse button is depressed or
          released, a new mouse event is queued by the event mecha-
          nism.  Emouse returns the next mouse event from the queue,
          blocking until the queue is non-empty.  Emouse returns a
          Mouse structure:

               struct Mouse
                     int   buttons;
                     Point xy;
                     ulong msec;

          Buttons&1 is set when the left mouse button is depressed,
          buttons&2 when the middle button is depressed, and buttons&4
          when the right button is depressed.  The current mouse posi-
          tion is always returned in xy.  Msec is a time stamp in
          units of milliseconds.

          Ecankbd and ecanmouse return non-zero when there are key-
          board or mouse events available to be read.

          Estart can be used to register additional file descriptors
          to scan for input.  It takes as arguments the file descrip-
          tor to register, the maximum length of an event message on
          that descriptor, and a key to be used in accessing the
          event.  The key must be a power of 2 and must not conflict
          with any previous keys.  If a zero key is given, one will be
          allocated and returned.  Ekeyboard and Emouse are the mouse
          and keyboard event keys.

          Etimer starts a repeating timer with a period of n millisec-
          onds.  Only one timer can be started.  Extra timer events
          are not queued and the timer channel has no associated data.

          Eread waits for the next event specified by the mask keys of
          event keys submitted to estart.  It fills in the appropriate
          field of the argument Event structure, which looks like:

               struct Event
                     int   kbdc;
                     Mouse mouse;
                     int   n;

     EVENT(2G)                                               EVENT(2G)

                     uchar data[EMAXMSG];

          Data is an array which is large enough to hold a 9P message.
          Eread returns the key for the event which was chosen.  For
          example, if a mouse event was read, Emouse will be returned.

          Event waits for the next event of any kind.  The return is
          the same as for eread.

          As described in graphics(2), the graphics functions are buf-
          fered.  Event, eread, emouse, and ekbd all cause a buffer
          flush unless there is an event of the appropriate type
          already queued.

          Getrect prompts the user to sweep a rectangle.  It should be
          called with m holding the mouse event that triggered the
          getrect (or, if none, a Mouse with buttons set to 7).  It
          changes to the sweep cursor, waits for the buttons all to be
          released, and then waits for button number but to be
          depressed, marking the initial corner.  If another button is
          depressed instead, getrect returns a rectangle with zero for
          both corners, after waiting for all the buttons to be
          released.  Otherwise, getrect continually draws the swept
          rectangle until the button is released again, and returns
          the swept rectangle.  The mouse structure pointed to by m
          will contain the final mouse event.

          Menuhit displays a menu and returns a selected menu item
          number.  It should be called with m holding the mouse event
          that triggered the menuhit; it will call emouse to update
          it.  A Menu is a structure:

               struct Menu
                     char  **item;
                     char  *(*gen)(int);
                     int   lasthit;

          If item is nonzero, it should be a null-terminated array of
          the character strings to be displayed as menu items.  Other-
          wise, gen should be a function that, given an item number,
          returns the character string for that item, or zero if the
          number is past the end of the list.  Items are numbered
          starting at zero.  Menuhit waits until but is released, and
          then returns the number of the selection, or -1 for no
          selection.  The m argument is filled in with the final mouse

          8½(1), graphics(2), cons(3), bit(3)