Felisp
84436a5ae0
http://my.svgalib.org/svgalib/svgalib-1.9.25.tar.gz http://my.svgalib.org/svgalib/
161 lines
4.2 KiB
Groff
161 lines
4.2 KiB
Groff
.TH vga_waitevent 3 "27 July 1997" "Svgalib (>= 1.2.11)" "Svgalib User Manual"
|
|
.SH NAME
|
|
vga_waitevent \- wait for various I/O events
|
|
.SH SYNOPSIS
|
|
|
|
.B "#include <sys/time.h>"
|
|
.br
|
|
.B "#include <sys/types.h>"
|
|
.br
|
|
.B "#include <unistd.h>"
|
|
.br
|
|
.B "#include <vga.h>"
|
|
|
|
.BI "int vga_waitevent(int " which ", fd_set *" input ", fd_set *" output
|
|
.BI ", fd_set *" except ", struct timeval *" timeout)
|
|
|
|
.SH DESCRIPTION
|
|
This is the only function allowing you to wait for keyboard
|
|
AND mouse events. It is based on the
|
|
.BR select (2)
|
|
library function,
|
|
so for deep understanding of
|
|
.B vga_waitevent()
|
|
look at
|
|
.BR select (2)
|
|
as well.
|
|
|
|
.I which
|
|
can be 0 or logical ored together from
|
|
.BR 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
|
|
.B fd_set
|
|
structures passed (see
|
|
.BR select (3)).
|
|
If you want
|
|
.B vga_waitevent()
|
|
to return after a timeout value pass a
|
|
.B struct timeval
|
|
with the desired value. If you are not interested in the
|
|
corresponding events you may pass
|
|
.B NULL
|
|
for any of the pointers.
|
|
|
|
If
|
|
.B NULL
|
|
is passed for
|
|
.IB "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
|
|
.B errno
|
|
for details. If a value >= 0 is returned it is a bitmask constructed using
|
|
.BR 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
|
|
.BR vga_waitevent() . vga_waitevent()
|
|
operates in raw as well as non-raw keyboard
|
|
mode. In the latter case use
|
|
.BR vga_getch (3)
|
|
not
|
|
.BR 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
|
|
.B fd_set
|
|
structures. If a
|
|
.RB non- NULL
|
|
.I timeout
|
|
is passed the remaining time is written into it on return.
|
|
If it is 0 a timeout occured. (again: cf.
|
|
.BR select (2))
|
|
Therefore, depending on context,
|
|
.BR vga_waitkey (3)
|
|
may return 0 if only special, non svgalib, events occured.
|
|
|
|
.SH EXAMPLES
|
|
If you want to wait blocking for a keypress OR a mouse event use:
|
|
.B 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:
|
|
|
|
.B "#include <sys/time.h>"
|
|
.br
|
|
.B "#include <sys/types.h>"
|
|
.br
|
|
.B "#include <unistd.h>"
|
|
.br
|
|
.B "#include <vga.h>"
|
|
|
|
.B struct timeval timeout;
|
|
.br
|
|
.B timeout.tv_sec = 0;
|
|
.br
|
|
.B timeout.tv_usec = 0;
|
|
.br
|
|
.B vga_waitevent(VGA_MOUSEEVENT | VGA_KEYEVENT, NULL, NULL, NULL, &timeout);
|
|
|
|
You could do a similar thing by just calling
|
|
|
|
.B mouse_update();
|
|
.br
|
|
.B keyboard_update();
|
|
|
|
though. There is no such counterpart for the first example.
|
|
|
|
Finally, there is a very nice
|
|
.BR eventtest (6)
|
|
demo showing most capabilities of
|
|
.BR vga_waitevent() .
|
|
|
|
.SH BUGS
|
|
This function was introduced in 1.2.10. Unfortunately there was a typo in the first
|
|
implementation which broke the case where
|
|
.I input
|
|
was
|
|
.BR NULL .
|
|
Though fixed in 1.2.11 for optimal portability pass an empty
|
|
.B fd_set
|
|
instead of
|
|
.B 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
|
|
.B vga_waitevent
|
|
gets stuck and does no longer timeout. It is not clear if this is an svgalib bug, kernel
|
|
bug or general problem.
|
|
|
|
.SH SEE ALSO
|
|
|
|
.BR svgalib (7),
|
|
.BR vgagl (7),
|
|
.BR libvga.config (5),
|
|
.BR eventtest (6),
|
|
.BR mouse_getposition_6d (3),
|
|
.BR mouse_getx (3),
|
|
.BR mouse_update (3),
|
|
.BR mouse_waitforupdate (3),
|
|
.BR vga_getkey (3),
|
|
.BR vga_getch (3)
|
|
|
|
.SH 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.
|