'\" t
.\"     Title: xiquerydevice
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.74.3 <http://docbook.sf.net/>
.\"      Date: 10/02/2009
.\"    Manual: [FIXME: manual]
.\"    Source: [FIXME: source]
.\"  Language: English
.\"
.TH "XIQUERYDEVICE" "libmansuffix" "10/02/2009" "[FIXME: source]" "[FIXME: manual]"
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.SH "NAME"
XIQueryDevice, XIFreeDeviceInfo \- get information about devices\&.
.SH "SYNOPSIS"
.sp
.nf
#include <X11/extensions/XInput2\&.h>
.fi
.sp
.nf
XIDeviceInfo* XIQueryPointer( Display *display,
                              int deviceid,
                              int *ndevices_return);
.fi
.sp
.nf
XIFreeDeviceInfo( XIDeviceInfo *info);
.fi
.sp
.nf
deviceid
       Specifies the device to query or XIAllDevices or
       XIAllMasterDevices\&.
.fi
.sp
.nf
display
       Specifies the connection to the X server\&.
.fi
.sp
.nf
ndevices_return
       Returns the number of devices returned\&.
.fi
.sp
.nf
info
       A list of device XIDeviceInfo structs to be freed\&.
.fi
.SH "DESCRIPTION"
.sp
.if n \{\
.RS 4
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.nf
The XIQueryDevice returns information about one or more input
devices\&. If the deviceid specifies a device, ndevices_return is
1 and the returned information describes only the requested
device\&. If deviceid is XIAllDevices or XIAllMasterDevices,
ndevices_return is the number of devices or master devices,
respectively, and the returned information represents all
devices or all master devices, respectively\&.
.fi
.if n \{\
.RE
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.sp
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.RS 4
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.nf
To free the XIDeviceInfo array returned by XIQueryDevice, use
XIFreeDeviceInfo\&.
.fi
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.RE
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.sp
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.RS 4
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.nf
For each input device requested, the XIQueryDevice returns an
XIDeviceInfo structure\&. Each structure contains information
about the capabilities of one input device available to the
server\&.
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.RE
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typedef struct
{
    int                 deviceid;
    char                *name;
    int                 use;
    int                 attachment;
    Bool                enabled;
    int                 num_classes;
    XIAnyClassInfo      **classes;
} XIDeviceInfo;
.fi
.if n \{\
.RE
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.RS 4
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.nf
The deviceid is the numeric unique id of the device\&. A deviceid
is unique for the life\-time of a device but a server may re\-use
the id once a device has been removed\&.
.fi
.if n \{\
.RE
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.sp
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.RS 4
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.nf
The name points to a null\-terminated string specifying the
identifier of the device\&.
.fi
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.RE
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.RS 4
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.nf
The use and attachment fields specify the type of the device
and the current attachment or pairing\&.
\- If use is XIMasterPointer, the device is a master pointer and
  attachment specifies the deviceid of the paired master
  keyboard\&.
\- If use is XIMasterKeyboard, the device is a master keyboard,
  and the attachment field specifies the paired master pointer\&.
\- If use is XISlavePointer, the device is a slave device and
  currently attached to the master pointer specified in
  attachement\&.
\- If use is XISlaveKeyboard, the device is a slave device an
  currently attached to the master keyboard specified in
  attachment\&.
\- If use is XIFloatingSlave, the device is a slave device
  currently not attached to any master device\&. The value of the
  attachment field for floating slave devices is undefined\&.
.fi
.if n \{\
.RE
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The enabled field specifies if the device is currently enabled
and can send events\&. Disabled devices will not send events\&.
.fi
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.RE
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.nf
The num_classes field specifies the number of input classes
pointed to by classes\&. The first two fields of all input
classes are identical\&.
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typedef struct
{
    int         type;
    int         sourceid;
} XIAnyClassInfo;
.fi
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The type field specifies the type of the input class\&.
Currently, the following types are defined:
    XIKeyClass, XIButtonClass, XIValuatorClass
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.nf
In the future, additional types may be added\&. Clients are
required to ignore unknown input classes\&.
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The sourceid is the deviceid this class originated from\&. For
master devices, the sourceid is typically the id of the slave
device currently sending events\&. For slave devices, the
sourceid is typically the device\'s id\&.
.fi
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A device may have zero or one XIButtonClass, denoting the
device\'s capability to send button events\&.
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typedef struct {
    int           mask_len;
    unsigned char *mask;
} XIButtonState;
.fi
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.nf
typedef struct
{
    int         type;
    int         sourceid;
    int         num_buttons;
    Atom        *labels;
    XIButtonState state;
} XIButtonClassInfo;
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
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.nf
The num_buttons field specifies the number of buttons available
on this device\&. A device that has an XIButtonClass must have at
least one button\&.
.fi
.if n \{\
.RE
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.sp
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.RS 4
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.nf
labels is a list of num_buttons Atoms specifying the button
labels for this device\&. If the label is not None, then the
label specifies the type of button in physical device order
(i\&.e\&. as the buttons are numbered on the physical input
device)\&.
.fi
.if n \{\
.RE
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.sp
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.nf
The state is the current button state as seen by clients (i\&.e\&.
after button mapping is applied)\&. The mask_len field specifies
the length of mask in bytes\&. For each button on the device, the
respective bit in mask is set if the button is currently
logically down\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
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.nf
A device may have zero or one XIKeyClass, denoting the device\'s
capability to send key events\&.
.fi
.if n \{\
.RE
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.sp
.if n \{\
.RS 4
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.nf
typedef struct
{
    int         type;
    int         sourceid;
    int         num_keycodes;
    int         *keycodes;
} XIKeyClassInfo;
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
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.nf
The num_keycodes field specifies the number of keycodes
available on this device\&. A device that has an XIKeyClass must
have at least one keycode\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
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.nf
keycodes is a list of num_keycodes keycodes the device may
send\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
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.nf
A device may have zero or more XIValuatorClass, denoting the
device\'s capability to send coordinates\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
typedef struct
{
    int         type;
    int         sourceid;
    int         number;
    Atom        label;
    double      min;
    double      max;
    double      value;
    int         resolution;
    int         mode;
} XIValuatorInfo;
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
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.nf
The number field specifies the number of the axis on the
physical device\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
If the label field is not None, the value of label is an Atom
describing the axis\&.
.fi
.if n \{\
.RE
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.sp
.if n \{\
.RS 4
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.nf
min and max are the minimum and maximum values allowed on this
axis\&. If both are zero, no minumum or maximum values are set on
this device\&. value is the current value of this axis\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
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.nf
The resolution field specifies the resolution of the device in
units/m\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
The mode specifies the mode of this axis\&. If the mode is
XIModeAbsolute this axis sends absolute coordinates\&. If the
mode is XIModeRelative, this device sends relative coordinates\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
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.nf
XIQueryDevice can generate a BadDevice error\&.
.fi
.if n \{\
.RE
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.sp
.if n \{\
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.nf
XIFreeDeviceInfo frees the information returned by
XIQueryDevice\&.
.fi
.if n \{\
.RE
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.SH "DIAGNOSTICS"
.sp
.if n \{\
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.nf
BadDevice
       An invalid device was specified\&. The device does not
       exist or is not a pointer device\&.
.fi
.if n \{\
.RE
.\}