NAME

       XQueryExtension, XListExtensions, XFreeExtensionList - list available extensions

SYNTAX

       Bool XQueryExtension(display, name, major_opcode_return, first_event_return, first_error_return)

       char **XListExtensions(display, nextensions_return)

       XFreeExtensionList(list)

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.

       first_error_return
                 Returns the first error code, if any.

       nextensions_return
                 Returns the number of extensions listed.

       list      Specifies the list of extension names.

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.
       If  the  extension  name  is  not  in  the Host Portable Character Encoding the result is implementation-
       dependent.  Uppercase and lowercase matter; the strings “thing”, “Thing”, and “thinG” are all  considered
       different names.

       The  XListExtensions  function  returns  a  list  of all extensions supported by the server.  If the data
       returned by the server is in the Latin Portable Character Encoding, then the returned strings are in  the
       Host Portable Character Encoding.  Otherwise, the result is implementation-dependent.

       The XFreeExtensionList function frees the memory allocated by XListExtensions.