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.