XQueryExtension(3) X FUNCTIONS XQueryExtension(3)
NAME
XQueryExtension, XListExtensions, XFreeExtensionList - list available
extensions
SYNTAX
Bool XQueryExtension(display, name, major_opcode_return, first_event_re-
turn, 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_op-
code_return; otherwise, it returns zero. Any minor opcode and the re-
quest 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 addi-
tional error codes, XQueryExtension returns the base error code to
first_error_return; otherwise, it returns zero. The format of addi-
tional data in the errors is specific to the extension. If the exten-
sion 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 XListEx-
tensions.
X Version 11 libX11 1.8.12 XQueryExtension(3)
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