'\" t
.\"     Title: xquerydevicestate
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: 09/15/2021
.\"    Manual: \ \&
.\"    Source: \ \&
.\"  Language: English
.\"
.TH "XQUERYDEVICESTATE" "libmansuffix" "09/15/2021" "\ \&" "\ \&"
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.SH "NAME"
XQueryDeviceState \- query the state of an extension input device\&.
.SH "SYNOPSIS"
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#include <X11/extensions/XInput\&.h>
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XDeviceState* XQueryDeviceState( Display *display,
                                 XDevice *device);
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display
       Specifies the connection to the X server\&.
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device
       Specifies the device whose state is to be queried\&.
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.SH "DESCRIPTION"
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The XQueryDeviceState request queries the state of an input
device\&. The current state of keys and buttons (up or down), and
valuators (current value) on the device is reported by this
request\&. Each key or button is represented by a bit in the
XDeviceState structure that is returned\&. Valuators on the
device report 0 if they are reporting relative information, and
the current value if they are reporting absolute information\&.
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XQueryDeviceState can generate a BadDevice error\&.
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Structures:
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The XDeviceState structure contains:
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typedef struct {
    XID device_id;
    int num_classes;
    XInputClass *data;
} XDeviceState;
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The XValuatorState structure contains:
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typedef struct {
    unsigned char class;
    unsigned char length;
    unsigned char num_valuators;
    unsigned char mode;
    int *valuators;
} XValuatorState;
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The XKeyState structure contains:
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typedef struct {
    unsigned char class;
    unsigned char length;
    short     num_keys;
    char keys[32];
} XKeyState;
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The XButtonState structure contains:
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typedef struct {
    unsigned char class;
    unsigned char length;
    short     num_buttons;
    char buttons[32];
} XButtonState;
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.SH "DIAGNOSTICS"
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BadDevice
       An invalid device was specified\&. The specified device
       does not exist or has not been opened by this client via
       XOpenInputDevice\&. This error may also occur if some
       other client has caused the specified device to become
       the X keyboard or X pointer device via the
       XChangeKeyboardDevice or XChangePointerDevice requests\&.
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