xkbqueryextension(3) [centos man page]
XkbQueryExtension(3) XKB FUNCTIONS XkbQueryExtension(3) 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 check- ing 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 func- tions. 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 compati- ble 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) X Version 11 libX11 1.6.0 XkbQueryExtension(3)
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XkbOpenDisplay(3) XKB FUNCTIONS XkbOpenDisplay(3) NAME
XkbOpenDisplay - Checks for a compatible version of the Xkb extension in both the library and the server, and initializes the extension for use. SYNOPSIS
Display XkbOpenDisplay (char *display_name, int *event_rtrn, int *error_rtrn, int *major_in_out, int *minor_in_out, int *reason_rtrn); ARGUMENTS
display_name hardware display name, which determines the display and communications domain to be used 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 reason_rtrn backfilled with a status code DESCRIPTION
As a convenience, you can use the function XkbOpenDisplay to perform these three tasks at once: open a connection to an X server, check for a compatible version of the Xkb extension in both the library and the server, and initialize the extension for use. XkbOpenDisplay is a convenience function that opens an X display connection and initializes the X keyboard extension. In all cases, upon return reason_rtrn contains a status value indicating success or the type of failure. If major_in_out and minor_in_out are not NULL, XkbOpenDisplay first calls XkbLibraryVersion to determine whether the client library is compatible, passing it the values pointed to by major_in_out and minor_in_out. If the library is incompatible, XkbOpenDisplay backfills major_in_out and minor_in_out with the major and minor extension versions of the library being used and returns NULL. If the library is compatible, XkbOpenDisplay next calls XOpenDisplay with the display_name. If this fails, the function returns NULL. If successful, XkbOpenDisplay calls XkbQueryExtension and backfills the major and minor Xkb server extension version numbers in major_in_out and minor_in_out. If the server extension version is not compatible with the library extension version or if the server extension is not present, XkbOpenDisplay closes the display and returns NULL. When suc- cessful, the function returns the display connection. The possible values for reason_rtrn are: o XkbOD_BadLibraryVersion indicates XkbLibraryVersion returned False. o XkbOD_ConnectionRefused indicates the display could not be opened. o XkbOD_BadServerVersion indicates the library and the server have incompatible extension versions. o XkbOD_NonXkbServer indicates the extension is not present in the X server. o XkbOD_Success indicates that the function succeeded. RETURN VALUES
NULL The XkbOpenDisplay function returns NULL if the library is incompatible. The XkbOpenDisplay function returns NULL if the call to XOpenDisplay with the display_name fails. The XkbOpenDisplay function returns NULL and closes the display if the server extension version is not compatible with the library extension version or if the server extension is not present. DIAGNOSTICS
BadAccess The Xkb extension has not been properly initialized SEE ALSO
XkbLibraryVersion(3), XkbQueryExtension(3), XOpenDisplay(3) X Version 11 libX11 1.5.0 XkbOpenDisplay(3)