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XISELECTEVENTS
Section: \ \& (3)Updated: 03/09/2013
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NAME
XISelectEvents, XIGetSelectedEvents - select for or get selected XI2 events on the window.SYNOPSIS
#include <X11/extensions/XInput2.h>
Status XISelectEvents( Display *display,
Window win,
XIEventMask *masks,
int num_masks);
display
Specifies the connection to the X server.
masks
Device event mask.
num_masks
Number of masks in masks.
win
Specifies the window.
XIEventMask *XIGetSelectedEvents( Display *display,
Window win,
int *num_masks_return);
display
Specifies the connection to the X server.
num_masks_return
Number of masks in the return value.
win
Specifies the window.
DESCRIPTION
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XI2 events must be selected using XISelectEvents.
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XISelectEvents sets the event mask for this client on win. Further events are only reported to this client if the event type matches the selected event mask. The masks overrides the previously selected event mask for the given device.
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If deviceid is a valid device, the event mask is selected only for this device. If deviceid is XIAllDevices or XIAllMasterDevices, the event mask is selected for all devices or all master devices, respectively. The effective event mask is the bit-wise OR of the XIAllDevices, XIAllMasterDevices and the respective device's event mask.
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typedef struct { int deviceid; int mask_len; unsigned char* mask; } XIEventMask;
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The mask_len specifies the length of mask in bytes. mask is a binary mask in the form of (1 << event type). deviceid must be either a device or XIAllDevices or XIAllMasterDevices. A client may submit several masks with the same deviceid in one request but only the last mask will be effective.
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XISelectEvents can generate a BadValue, a BadDevice, and a BadWindow error.
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XIGetSelectedEvents returns the events selected by this client on the given window. If no events were selected on this window, XIGetSelectedEvents returns NULL and num_masks_return is set to 0. If an internal error occurs, XIGetSelectedEvents returns NULL and num_masks_return is set to -1. Otherwise, XIGetSelectedEvent returns the selected event masks for all devices including the masks for XIAllDevices and XIAllMasterDevices
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The caller must free the returned data using XFree().
DIAGNOSTICS
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BadValue A value is outside of the permitted range.
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BadWindow A value for a Window argument does not name a defined window.
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BadDevice An invalid device was specified. The device does not exist.