XkbQueryExtension - Determines the compatibility of a library at runtime.

dpy    connection to the X server

       opcode_rtrn
              backfilled with the major extension opcode

       event_rtrn
              backfilled with the extension base event code

       error_rtrn
              backfilled with the extension base error code

       major_in_out
              compile time lib major version in, server major version out

       minor_in_out
              compile time lib min version in, server minor version out

       Call XkbQueryExtension to check for the presence and compatibility of the extension in the server and  to
       initialize  the  extension. Because of potential version mismatches, you cannot use the generic extension
       mechanism functions ( XQueryExtension and  XInitExtension  )  for  checking  for  the  presence  of,  and
       initializing the Xkb extension.

       You  must  call XkbQueryExtension or XkbOpenDisplay before using any other Xkb library interfaces, unless
       such usage is explicitly allowed in the interface description  in  this  document.  The  exceptions  are:
       XkbIgnoreExtension,XkbLibraryVersion,  and  a handful of audible-bell functions. You should not use any
       other Xkb functions if the extension is not present or is uninitialized. In general, calls to Xkb library
       functions made prior to initializing the Xkb extension cause BadAccess protocol errors.

       XkbQueryExtension both determines whether a compatible Xkb extension is  present  in  the  X  server  and
       initializes the extension when it is present.

       The  XkbQueryExtension  function  determines  whether a compatible version of the X Keyboard Extension is
       present in the server. If a compatible extension is present, XkbQueryExtension returns  True;  otherwise,
       it returns False.

       If  a compatible version of Xkb is present, XkbQueryExtension initializes the extension. It backfills the
       major opcode for the keyboard extension in opcode_rtrn, the base event code in event_rtrn, the base error
       code in error_rtrn, and the major and  minor  version  numbers  of  the  extension  in  major_in_out  and
       minor_in_out.   The major opcode is reported in the req_major fields of some Xkb events. For a discussion
       of the base event code.

       XkbQueryExtension -  Determines the compatibility of a library at runtime.

       True           The XkbQueryExtension function returns True if it determines a compatible version of the X
                      Keyboard Extension is present in the server.

       False          The XkbQueryExtension function returns False if it determines a compatible version of  the
                      X Keyboard Extension is not present in the server.

XkbIgnoreExtension(3), XkbLibraryVersion(3), XkbOpenDisplay(3)

X Version 11                                      libX11 1.8.12                             XkbQueryExtension(3)

BoolXkbQueryExtension(Display*dpy,int*opcode_rtrn,int*event_rtrn,int*error_rtrn,int*major_in_out,int*minor_in_out);