NAME

       XkbQueryExtension -  Determines the compatibility of a library at runtime.

SYNOPSIS

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

ARGUMENTS

       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

DESCRIPTION

       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.

RETURN VALUES

       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.

SEE ALSO

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