xcb_query_tree(3) XCB Requests xcb_query_tree(3)
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_t *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);
}
}
SEE ALSO
xcb-requests(3), xcb-examples(3), xwininfo(1)
AUTHOR
Generated from xproto.xml. Contact xcb@lists.freedesktop.org for cor-
rections and improvements.
X Version 11 libxcb 1.12 xcb_query_tree(3)
xorg-libxcb 1.12 - Generated Mon May 30 14:00:27 CDT 2016