Function get_property

pub fn get_property<Conn, A, B>(
    conn: &Conn,
    delete: bool,
    window: Window,
    property: A,
    type_: B,
    long_offset: u32,
    long_length: u32,
) -> Result<Cookie<'_, Conn, GetPropertyReply>, ConnectionError>
where
    Conn: RequestConnection + ?Sized,
    A: Into<Atom>,
    B: Into<Atom>,

Gets a window property.

Gets the specified property from the specified window. Properties are for example the window title (WM_NAME) or its minimum size (WM_NORMAL_HINTS). Protocols such as EWMH also use properties - for example EWMH defines the window title, encoded as UTF-8 string, in the _NET_WM_NAME property.

TODO: talk about type

TODO: talk about delete

TODO: talk about the offset/length thing. what’s a valid use case?

Fields

• window - The window whose property you want to get.
• delete - Whether the property should actually be deleted. For deleting a property, the specified type has to match the actual property type.
• property - The property you want to get (an atom).
• type - The type of the property you want to get (an atom).
• long_offset - Specifies the offset (in 32-bit multiples) in the specified property where the data is to be retrieved.
• long_length - Specifies how many 32-bit multiples of data should be retrieved (e.g. if you set long_length to 4, you will receive 16 bytes of data).

Errors

• Window - The specified window does not exist.
• Atom - property or type do not refer to a valid atom.
• Value - The specified long_offset is beyond the actual property length (e.g. the property has a length of 3 bytes and you are setting long_offset to 1, resulting in a byte offset of 4).

See

• InternAtom: request
• xprop: program

Example

/*
 * Prints the WM_NAME property of the window.
 *
 */
void my_example(xcb_connection_t *c, xcb_window_t window) {
    xcb_get_property_cookie_t cookie;
    xcb_get_property_reply_t *reply;

    /* These atoms are predefined in the X11 protocol. */
    xcb_atom_t property = XCB_ATOM_WM_NAME;
    xcb_atom_t type = XCB_ATOM_STRING;

    // TODO: a reasonable long_length for WM_NAME?
    cookie = xcb_get_property(c, 0, window, property, type, 0, 0);
    if ((reply = xcb_get_property_reply(c, cookie, NULL))) {
        int len = xcb_get_property_value_length(reply);
        if (len == 0) {
            printf("TODO\\n");
            free(reply);
            return;
        }
        printf("WM_NAME is %.*s\\n", len,
               (char*)xcb_get_property_value(reply));
    }
    free(reply);
}