1XSETDEVICEFOCUS(3)                                          XSETDEVICEFOCUS(3)
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NAME

6       XSetDeviceFocus, XGetDeviceFocus - control extension input device focus
7

SYNOPSIS

9       #include <X11/extensions/XInput.h>
10
11       XSetDeviceFocus( Display *display,
12                        XDevice *device,
13                        Window focus,
14                        int revert_to,
15                        Time time);
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17       XGetDeviceFocus( Display *display,
18                        XDevice *device,
19                        Window *focus_return,
20                        int *revert_to_return,
21                        int * time_return);
22
23       Arguments
24
25       display
26              Specifies the connection to the X server.
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28       device
29              Specifies the device whose focus is to be queried or
30              changed.
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32       focus
33              Specifies the window, PointerRoot, FollowKeyboard,or
34              None.
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36       focus_return
37              Returns the focus window, PointerRoot, FollowKeyboard,or
38              None.
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40       revert_to
41              Specifies where the input focus reverts to if the window
42              becomes notviewable.You can pass RevertToParent,
43              RevertToPointerRoot, RevertToFollowKeyboard,or
44              RevertToNone.
45
46       revert_to_return
47              Returns the current focus state RevertToParent,
48              RevertToPointerRoot, RevertToFollowKeyboard,or
49              RevertToNone.
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51       time_return
52              Returns the last_focus_time for the device.
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54       time
55              Specifies the time.You can pass either a timestamp or
56              CurrentTime.
57

DESCRIPTION

59           The XSetDeviceFocus request changes the focus of the specified
60           device and its last-focus-change time. It has no effect if the
61           specified time is earlier than the current last-focus-change
62           time or is later than the current X server time. Otherwise, the
63           last-focus-change time is set to the specified time CurrentTime
64           is replaced by the current X server time). XSetDeviceFocus
65           causes the X server to generate DeviceFocusIn and
66           DeviceFocusOut events.
67
68           Depending on the focus argument, the following occurs:
69             * If focus is None , all device events are discarded until a
70               new focus window is set, and the revert_to argument is
71               ignored.
72             * If focus is a window, it becomes the device's focus window.
73               If a generated device event would normally be reported to
74               this window or one of its inferiors, the event is reported
75               as usual. Otherwise, the event is reported relative to the
76               focus window.
77             * If focus is PointerRoot, the focus window is dynamically
78               taken to be the root window of whatever screen the pointer
79               is on at each event from the specified device. In this
80               case, the revert_to argument is ignored.
81             * If focus is FollowKeyboard, the focus window is dynamically
82               taken to be the window to which the X keyboard focus is set
83               at each input event.
84
85           The specified focus window must be viewable at the time
86           XSetDeviceFocus is called, or a BadMatch error results. If the
87           focus window later becomes not viewable, the X server evaluates
88           the revert_to argument to determine the new focus window as
89           follows:
90             * If revert_to is RevertToParent, the focus reverts to the
91               parent (or the closest viewable ancestor), and the new
92               revert_to value is taken to be RevertToNone.
93             * If revert_to is RevertToPointerRoot,
94               RevertToFollowKeyboard, or RevertToNone, the focus reverts
95               to PointerRoot, FollowKeyboard, or None, respectively.
96
97           When the focus reverts, the X server generates DeviceFocusIn
98           and DeviceFocusOut events, but the last-focus-change time is
99           not affected.
100
101           Input extension devices are not required to support the ability
102           to be focused. Attempting to set the focus of a device that
103           does not support this request will result in a BadMatch error.
104           Whether or not given device can support this request can be
105           determined by the information returned by XOpenDevice. For
106           those devices that support focus, XOpenDevice will return an
107           XInputClassInfo structure with the input_class field equal to
108           the constant FocusClass (defined in the file XI.h).
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110           XSetDeviceFocus can generate BadDevice, BadMatch, BadValue, and
111           BadWindow errors.
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113           The XGetDeviceFocus request returns the focus window and the
114           current focus state.
115
116           Not all input extension devices can be focused. Attempting to
117           query the focus state of a device that can't be focused results
118           in a BadMatch error. A device that can be focused returns
119           information for input Class Focus when an XOpenDevice request
120           is made.
121
122           XGetDeviceFocus can generate BadDevice, and BadMatch errors.
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DIAGNOSTICS

125           BadDevice
126                  An invalid device was specified. The specified device
127                  does not exist or has not been opened by this client via
128                  XOpenInputDevice. This error may also occur if the
129                  specified device is the X keyboard or X pointer device.
130
131           BadValue
132                  Some numeric value falls outside the range of values
133                  accepted by the request. Unless a specific range is
134                  specified for an argument, the full range defined by the
135                  argument's type is accepted. Any argument defined as a
136                  set of alternatives can generate this error.
137
138           BadWindow
139                  A value for a Window argument does not name a defined
140                  Window.
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142           BadMatch
143                  This error may occur if an XGetDeviceFocus or
144                  XSetDeviceFocus request was made specifying a device
145                  that the server implementation does not allow to be
146                  focused.
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150                                  03/09/2013                XSETDEVICEFOCUS(3)
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