xcb_query_extension(3) XCB Requests xcb_query_extension(3)
NAME
xcb_query_extension - check if extension is present
SYNOPSIS
#include <xcb/xproto.h> Request function
xcb_query_extension_cookie_t
xcb_query_extension(xcb_connection_t *
conn, uint16_t
name_len,
const char *
name);
Reply datastructure
typedef struct xcb_query_extension_reply_t {
uint8_t
response_type;
uint8_t
pad0;
uint16_t
sequence;
uint32_t
length;
uint8_t
present;
uint8_t
major_opcode;
uint8_t
first_event;
uint8_t
first_error;
}
xcb_query_extension_reply_t;
Reply function
xcb_query_extension_reply_t
*
xcb_query_extension_reply(xcb_connection_t *
conn,
xcb_query_extension_cookie_t
cookie, xcb_generic_error_t **
e);
REQUEST ARGUMENTS
conn The XCB connection to X11.
name_len The length of
name in bytes.
name The name of the extension to query, for example "RANDR".
This is case sensitive!
REPLY FIELDS
response_type The type of this reply, in this case
XCB_QUERY_EXTENSION.
This field is also present in the
xcb_generic_reply_t and
can be used to tell replies apart from each other.
sequence The sequence number of the last request processed by the
X11 server.
length The length of the reply, in words (a word is 4 bytes).
present Whether the extension is present on this X11 server.
major_opcode The major opcode for requests.
first_event The first event code, if any.
first_error The first error code, if any.
DESCRIPTION
Determines if the specified extension is present on this X11 server.
Every extension has a unique
major_opcode to identify requests, the
minor opcodes and request formats are extension-specific. If the
extension provides events and errors, the
first_event and
first_error fields in the reply are set accordingly.
There should rarely be a need to use this request directly, XCB
provides the
xcb_get_extension_data function instead.
RETURN VALUE
Returns an
xcb_query_extension_cookie_t. Errors have to be handled
when calling the reply function
xcb_query_extension_reply.
If you want to handle errors in the event loop instead, use
xcb_query_extension_unchecked. See
xcb-requests(3) for details.
ERRORS
This request does never generate any errors.
SEE ALSO
xcb-requests(3),
xcb_get_extension_data(3),
xdpyinfo(1)AUTHOR
Generated from xproto.xml. Contact xcb@lists.freedesktop.org for
corrections and improvements.
X Version 11 libxcb 1.16.1 xcb_query_extension(3)
