Manpages - xcb_query_tree.3

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_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);
      }
  }

AUTHOR

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