Provided by: libsvga1-dev_1.4.3-27ubuntu1_i386 bug

NAME

       vga_waitevent - wait for various I/O events

SYNOPSIS

       #include <sys/time.h>
       #include <sys/types.h>
       #include <unistd.h>
       #include <vga.h>

       int  vga_waitevent(int  which,  fd_set  *input, fd_set *output , fd_set
       *except, struct timeval *timeout)

DESCRIPTION

       This is the only function allowing you to wait for keyboard  AND  mouse
       events.  It  is  based  on  the select(2) library function, so for deep
       understanding of vga_waitevent() look at select(2) as well.

       which can be  0  or  logical  ored  together  from  VGA_MOUSEEVENT  and
       VGA_KEYEVENT.   If  you  are interested in waiting for file descriptors
       having input available or being ready for new write data or being in an
       exceptional  condition  (urgent  data  arrived on a TCP stream) set the
       corresponding bits in the fd_set structures passed (see select(3)).  If
       you  want vga_waitevent() to return after a timeout value pass a struct
       timeval with the desired value.  If  you  are  not  interested  in  the
       corresponding events you may pass NULL for any of the pointers.

       If  NULL  is  passed  for timeout vga_waitevent() will not time out but
       block until any of the other events occurs.  If the integer returned is
       <  0 an error occurred. Check the global variable errno for details. If
       a  value  >=  0  is  returned  it  is  a  bitmask   constructed   using
       VGA_MOUSEEVENT  and VGA_KEYEVENT to show which of these events occured.

       If any of these  two  occured  the  appropriate  update  functions  are
       already  called  by  vga_waitevent().vga_waitevent() operates in raw as
       well as non-raw keyboard mode. In the latter case use vga_getch(3)  not
       vga_getkey(3) to read the newly arrived keys.

       Any  of  the  file  related  conditions  being met will be signalled by
       setting exactly the bits for files  that  met  the  conditions  in  the
       corresponding  fd_set  structures.  If a non-NULL timeout is passed the
       remaining time is written into it on return.  If  it  is  0  a  timeout
       occured.  (again:  cf.   select(2))  Therefore,  depending  on context,
       vga_waitkey(3) may return  0  if  only  special,  non  svgalib,  events
       occured.

EXAMPLES

       If  you  want  to  wait  blocking  for a keypress OR a mouse event use:
       vga_waitevent(VGA_MOUSEEVENT | VGA_KEYEVENT, NULL, NULL, NULL, NULL);

       If you want to wait for a keypress OR a mouse  event  but  non-blocking
       use:

       #include <sys/time.h>
       #include <sys/types.h>
       #include <unistd.h>
       #include <vga.h>

       struct timeval timeout;
       timeout.tv_sec = 0;
       timeout.tv_usec = 0;
       vga_waitevent(VGA_MOUSEEVENT   |   VGA_KEYEVENT,   NULL,   NULL,  NULL,
       &timeout);

       You could do a similar thing by just calling

       mouse_update();
       keyboard_update();

       though. There is no such counterpart for the first example.

       Finally,  there  is  a  very  nice  eventtest(6)  demo   showing   most
       capabilities of vga_waitevent().

BUGS

       This  function was introduced in 1.2.10. Unfortunately there was a typo
       in the first implementation which broke the case where input was  NULL.
       Though  fixed  in  1.2.11  for optimal portability pass an empty fd_set
       instead of NULL as first argument.

       When not running in background mode, that is, the svgalib applcation is
       suspended  while  the  VC is switched away, it seems vga_waitevent gets
       stuck and does no longer timeout. It is not clear if this is an svgalib
       bug, kernel bug or general problem.

SEE ALSO

       svgalib(7),       vgagl(7),       libvga.config(5),       eventtest(6),
       mouse_getposition_6d(3),        mouse_getx(3),         mouse_update(3),
       mouse_waitforupdate(3), vga_getkey(3), vga_getch(3)

AUTHOR

       This  manual  page  was  edited by Michael Weller <eowmob@exp-math.uni-
       essen.de>. The exact source of the referenced function as  well  as  of
       the original documentation is unknown.

       It is very likely that both are at least to some extent are due to Harm
       Hanemaayer <H.Hanemaayer@inter.nl.net>.

       Occasionally this might be wrong. I hereby asked to be excused  by  the
       original author and will happily accept any additions or corrections to
       this first version of the svgalib manual.