.TH joystick_sethandler 3 "14 April 1998" "Svgalib 1.3.0" "Svgalib User Manual"
.SH NAME
joystick_sethandler, joystick_setdefaulthandler \- set the joystick event handler.
.SH SYNOPSIS

.B "#include <vgajoystick.h>"
.br
.BI "typedef void (*" __joystick_handler ") (int " event ", int " number ", char"
.IB value ", int " joydev );

.BI "void joystick_sethandler(int " joydev ", __joystick_handler " jh );
.br
.BI "void joystick_setdefaulthandler(int " joydev );

.SH DESCRIPTION
By default, each call to
.BR joystick_init (3)
enables the default handler for the opened joystick. This handler maintains a state table
which can be read by the 
.BR joystick_getaxis (3),
.BR joystick_getbutton (3),
.BR joystick_button1|2|3|4 (3),
.BR joystick_getb1|2|3|4 (3),
.BR joystick_x|y|z "(3) and "
.BR joystick_getx|y|z (3)
functions.

If you define an own handler, the following parameters are passed:

.RS
.HP
.I event
one of the following values:
.RS
.HP
.B JOY_EVENTBUTTONDOWN
a button was pressed.
.HP
.B JOY_EVENTBUTTONUP
a button was released.
.HP
.B JOY_EVENTAXIS
the joystick position was changed.
.RE

.IP
All other values are reserved for future use.

.HP
.I number
identifies the button or axis to which this event belongs.

.HP
.I value
for axis events the new position in range
.BR "-128 .. 127" . See
.BR joystick_getaxis (3)
for further comments on the range.

.HP
.I joydev
identifies the joystick affected (this allows to use one handler for many joysticks).
.RE

.IB joydev " = -1"
modifies the event handler of
all currently open joystick devices.

.SH CAVEATS
This function is only available in ELF versions of svgalib. Due to backwards
compatibility issues it cannot be used with shared a.out libs.

.SH SEE ALSO

.BR svgalib (7),
.BR vgagl (7),
.BR libvga.config (5),
.BR joytest (6),
.BR mjoytest (6),
.BR joystick_init (3),
.BR joystick_close (3),
.BR joystick_update (3),
.BR joystick_getnumaxes (3),
.BR joystick_getnumbuttons (3),
.BR joystick_getaxis (3),
.BR joystick_getbutton (3),
.BR joystick_button1 (3),
.BR joystick_getb1 (3),
.BR joystick_x (3),
.BR joystick_getx (3).

.SH AUTHOR

The svgalib joystick handler was mostly done by Daniel Engstr\\"om <daniel.engstrom@riksnett.no>.
Multiple joystick, VC switching support and code to glue it into svgalib by Michael Weller
<eowmob@exp-math.uni-essen.de>. Part of the code is based on code from C. Smith and
Vojtech Pavlik.