.Dd January 23, 1995
.Dt JOY 4
.Sh NAME
.Nm joy
.Nd joystick device driver
.Sh SYNOPSIS
.Cd device joy0 at isa? port "IO_GAME"
.Fd #include <machine/joystick.h>
.Sh DESCRIPTION
The joystick device driver allows applications to read the status of
the PC joystick.
.Pp
This device may be opened by only one process at a time.
.Pp
The joystick status is get in an structure joystick via a read()
call. The structure is defined in the header file as follows:
.Pp
.Bd -literal -offset indent
	struct joystick {
		int x;         /* x position */
		int y;         /* y position */
		int b1;	       /* button 1 status */
		int b2;	       /* button 2 status */
	};
.Ed
.Pp
Positions are typically in the range 0-2000.
.Ss One line perl example:
perl -e 'open(JOY,"/dev/joy0")||die;while(1)
.br
{sysread(JOY,$x,16);@j=unpack("iiii",$x);print "@j\\n";sleep(1);}'
.Ss ioctl calls
Several ioctl() calls are also available. They take an argument of
type int *
.Bl -tag -width JOY_SET_X_OFFSET 
.It Dv JOY_SET_TIMEOUT Fa int *limit
Set the time limit (in microseconds) for reading the joystick
status. Setting a value
too small may prevent to get correct values for the positions (which
are then set to -2147483648), however this can be useful if one is
only interested by the buttons status. 
.It Dv JOY_GET_TIMEOUT Fa int *limit
Get the time limit (in microseconds) used for reading the joystick
status. 
.It Dv JOY_SET_X_OFFSET Fa int *offset
Set the value to be added to the X position  when reading the joystick
status. 
.It Dv JOY_SET_Y_OFFSET Fa int *offset
Set the value to be added to the Y position  when reading the joystick
status. 
.It Dv JOY_GET_X_OFFSET Fa int *offset
Get the value which is added to the X position  when reading the joystick
status. 
.It Dv JOY_GET_Y_OFFSET Fa int *offset
Get the value which is added to the Y position  when reading the joystick
status. 
.Sh FILES
.Bl -tag -width /dev/joy?
.It Pa /dev/joy?
joystick device files
.Sh AUTHOR
Jean-Marc Zucconi <jmz@cabri.obs-besancon.fr>
.Sh HISTORY
The joystick driver appeared in FreeBSD 2.0.5.