'\" t
.\"     Title: xopendevice
.\"    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 "XOPENDEVICE" "libmansuffix" "09/15/2021" "\ \&" "\ \&"
.\" -----------------------------------------------------------------
.\" * Define some portability stuff
.\" -----------------------------------------------------------------
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" http://bugs.debian.org/507673
.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\" -----------------------------------------------------------------
.\" * set default formatting
.\" -----------------------------------------------------------------
.\" disable hyphenation
.nh
.\" disable justification (adjust text to left margin only)
.ad l
.\" -----------------------------------------------------------------
.\" * MAIN CONTENT STARTS HERE *
.\" -----------------------------------------------------------------
.SH "NAME"
XOpenDevice, XCloseDevice \- open or close an extension input device
.SH "SYNOPSIS"
.sp
.nf
#include <X11/extensions/XInput\&.h>
.fi
.sp
.nf
XDevice *XOpenDevice( Display *display,
                      XID device_id);
.fi
.sp
.nf
XCloseDevice( Display *display,
              XDevice *device);
.fi
.sp
.nf
display
       Specifies the connection to the X server\&.
.fi
.sp
.nf
device_id
       Specifies the id of the device to be opened
.fi
.sp
.nf
device
       Specifies the device to be closed
.fi
.SH "DESCRIPTION"
.sp
.if n \{\
.RS 4
.\}
.nf
The XOpenDevice request makes an input device accessible to a
client through input extension protocol requests\&. If
successful, it returns a pointer to an XDevice structure\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
The XCloseDevice request makes an input device inaccessible to
a client through input extension protocol requests\&. Before
terminating, and client that has opened input devices through
the input extension should close them via CloseDevice\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
When a client makes an XCloseDevice request, any active grabs
that the client has on the device are released\&. Any event
selections that the client has are deleted, as well as any
passive grabs\&. If the requesting client is the last client
accessing the device, the server may disable all access by X to
the device\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
XOpenDevice and XCloseDevice can generate a BadDevice error\&.
.fi
.if n \{\
.RE
.\}
.sp
Structures
.sp
.if n \{\
.RS 4
.\}
.nf
The XDevice structure returned by XOpenDevice contains:
             typedef struct {
             XID device_id;
             int num_classes;
             XInputClassInfo *classes;
             } XDevice;
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
The classes field is a pointer to an array of XInputClassInfo
structures\&. Each element of this array contains an event type
base for a class of input supported by the specified device\&.
The num_classes field indicates the number of elements in the
classes array\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
The XInputClassInfo structure contains:
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
typedef struct {
    unsigned char input_class;
    unsigned char event_type_base;
} XInputClassInfo;
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
The input_class field identifies one class of input supported
by the device\&. Defined types include KeyClass, ButtonClass,
ValuatorClass, ProximityClass, FeedbackClass, FocusClass, and
OtherClass\&. The event_type_base identifies the event type of
the first event in that class\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
The information contained in the XInputClassInfo structure is
used by macros to obtain the event classes that clients use in
making XSelectExtensionEvent requests\&. Currently defined macros
include DeviceKeyPress, DeviceKeyRelease, DeviceButtonPress,
DeviceButtonRelease, DeviceMotionNotify, DeviceFocusIn,
DeviceFocusOut, ProximityIn, ProximityOut, DeviceStateNotify,
DeviceMappingNotify, ChangeDeviceNotify,
DevicePointerMotionHint, DeviceButton1Motion,
DeviceButton2Motion, DeviceButton3Motion, DeviceButton4Motion,
DeviceButton5Motion, DeviceButtonMotion, DeviceOwnerGrabButton,
DeviceButtonPressGrab, and NoExtensionEvent\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
To obtain the proper event class for a particular device, one
of the above macros is invoked using the XDevice structure for
that device\&. For example,
             DeviceKeyPress (*device, type, eventclass);
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
returns the DeviceKeyPress event type and the eventclass for
DeviceKeyPress events from the specified device\&.
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
This eventclass can then be used in an XSelectExtensionEvent
request to ask the server to send DeviceKeyPress events from
this device\&. When a selected event is received via XNextEvent,
the type can be used for comparison with the type in the event\&.
.fi
.if n \{\
.RE
.\}
.SH "DIAGNOSTICS"
.sp
.if n \{\
.RS 4
.\}
.nf
BadDevice
       An invalid device was specified\&. The specified device
       does not exist, or is the X keyboard or X pointer\&. 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\&.
.fi
.if n \{\
.RE
.\}