XQueryExtension

Syntax

Bool XQueryExtension(display, name, major_opcode_return, first_event_return, first_error_return)
      Display *display;
      char *name;
      int *major_opcode_return;
      int *first_event_return;
      int *first_error_return;

Arguments

display Specifies the connection to the X server.
name Specifies the extension name.
major_opcode_return Returns the major opcode.
first_event_return Returns the first event code, if any.
Specifies the extension list.

Description

The XQueryExtension() function determines if the named extension is present. If the extension is not present, XQueryExtension() returns False; otherwise, it returns True. If the extension is present, XQueryExtension() returns the major opcode for the extension to major_opcode_return; otherwise, it returns zero. Any minor opcode and the request formats are specific to the extension. If the extension involves additional event types, XQueryExtension() returns the base event type code to first_event_return; otherwise, it returns zero. The format of the events is specific to the extension. If the extension involves additional error codes, XQueryExtension() returns the base error code to first_error_return; otherwise, it returns zero. The format of additional data in the errors is specific to the extension.

See also

XFreeExtensionList(), XListExtensions(), "Basic Protocol Support Routines".
Christophe Tronche, ch.tronche@computer.org