Bool XpQueryExtension ( display, event_base_return error_base_return
)
Display *display;
int *event_base_return;
int *error_base_return;
XpQueryExtension determines if the X Print Service Extension is present. It returns True if the extension is supported, otherwise False. If the extension is present, the base values for events and errors are returned, and can be used to decode incoming event and error values.
The X Print Service Extension is initialized on the first call to any X Print Service function; there is no need to explicitly initialize the X Print Service Extension.