]> xcb_query_tree

xcb_query_tree

NAME
SYNOPSIS
REQUEST ARGUMENTS
REPLY FIELDS
DESCRIPTION
RETURN VALUE
ERRORS
EXAMPLE
SEE ALSO
AUTHOR

NAME

xcb_query_tree − query the window tree

SYNOPSIS

#include <xcb/xproto.h>

Request function

xcb_query_tree_cookie_t xcb_query_tree(xcb_connection_t *conn, xcb_window_t window);

Reply datastructure

typedef struct xcb_query_tree_reply_t {
uint8_t response_type;
uint8_t pad0;
uint16_t sequence;
uint32_t length;
xcb_window_t root;
xcb_window_t parent;
uint16_t children_len;
uint8_t pad1[14];
} xcb_query_tree_reply_t;

Reply function

xcb_query_tree_reply_t *xcb_query_tree_reply(xcb_connection_t *conn, xcb_query_tree_cookie_t cookie, xcb_generic_error_t **e);

Reply accessors

	xcb_window_t *xcb_query_tree_children(const xcb_query_tree_request_t *reply);
	int xcb_query_tree_children_length(const xcb_query_tree_reply_t *reply);
	xcb_generic_iterator_t xcb_query_tree_children_end(const xcb_query_tree_reply_t *reply);

REQUEST ARGUMENTS


	conn		The XCB connection to X11.
	window		The window to query.

REPLY FIELDS

response_type

The type of this reply, in this case XCB_QUERY_TREE. 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).
	root		The root window of window.
	parent		The parent window of window.

children_len

The number of child windows.

DESCRIPTION

Gets the root window ID, parent window ID and list of children windows for the specified window. The children are listed in bottom-to-top stacking order.

RETURN VALUE

Returns an xcb_query_tree_cookie_t. Errors have to be handled when calling the reply function xcb_query_tree_reply.

If you want to handle errors in the event loop instead, use xcb_query_tree_unchecked. See xcb-requests(3) for details.

ERRORS

This request does never generate any errors.

EXAMPLE

/*
* Displays the root, parent and children of the specified window.
*
*/
void my_example(xcb_connection *conn, xcb_window_t window) {
xcb_query_tree_cookie_t cookie;
xcb_query_tree_reply_t *reply;

cookie = xcb_query_tree(conn, window);
if ((reply = xcb_query_tree_reply(conn, cookie, NULL))) {
printf("root = 0x%08x\n", reply->root);
printf("parent = 0x%08x\n", reply->parent);

xcb_window_t *children = xcb_query_tree_children(reply);
for (int i = 0; i < xcb_query_tree_children_length(reply); i++)
printf("child window = 0x%08x\n", children[i]);

free(reply);
}
}

AUTHOR

Generated from xproto.xml. Contact xcb@lists.freedesktop.org for corrections and improvements.