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XISelectEvents

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

 XI2 events must be selected using XISelectEvents.
 

 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.
 

 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.
 

 typedef struct {
     int deviceid;
     int mask_len;
     unsigned char* mask;
 } XIEventMask;
 

 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.
 

 XISelectEvents can generate a BadValue, a BadDevice, and a
 BadWindow error.
 

 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
 

 The caller must free the returned data using XFree().
 

DIAGNOSTICS

 BadValue
        A value is outside of the permitted range.
 

 BadWindow
        A value for a Window argument does not name a defined
        window.
 

 BadDevice
        An invalid device was specified. The device does not
        exist.