XkbGetDeviceInfoChanges - Query the changes that have occurred in the button actions or indicator names

dpy    connection to X server

       device_info
              structure to update with results

       changes
              contains notes of changes that have occurred

       The changes->changed field indicates which attributes of the device  specified  in  changes->device  have
       changed.  The  parameters  describing  the  changes  are  contained  in  the  other  fields  of  changes.XkbGetDeviceInfoChanges uses that information to call XkbGetDeviceInfo to obtain the  current  status  of
       those  attributes  that  have changed. It then updates the local description of the device in device_info
       with the new information.

       XkbGetDeviceInfoChanges  -  Query the changes that have occurred in the button actions or indicator names
       and indicator maps associated with an input extension device

XkbGetDeviceInfo(3)

X Version 11                                      libX11 1.8.12                       XkbGetDeviceInfoChanges(3)

StatusXkbGetDeviceInfoChanges(Display*dpy,XkbDeviceInfoPtrdevice_info,XkbDeviceChangesPtrchanges);