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)