Provided by: libxcb-doc_1.13.1-5build1_all bug

NAME

       xcb_get_property - Gets a window property

SYNOPSIS

       #include <xcb/xproto.h>

   Request function
       xcb_get_property_cookie_t xcb_get_property(xcb_connection_t *conn, uint8_t _delete,
              xcb_window_t window, xcb_atom_t property, xcb_atom_t type, uint32_t long_offset,
              uint32_t long_length);

   Reply datastructure
       typedef struct xcb_get_property_reply_t {
           uint8_t    response_type;
           uint8_t    format;
           uint16_t   sequence;
           uint32_t   length;
           xcb_atom_t type;
           uint32_t   bytes_after;
           uint32_t   value_len;
           uint8_t    pad0[12];
       } xcb_get_property_reply_t;

   Reply function
       xcb_get_property_reply_t *xcb_get_property_reply(xcb_connection_t *conn,
              xcb_get_property_cookie_t cookie, xcb_generic_error_t **e);

   Reply accessors
       void *xcb_get_property_value(const xcb_get_property_request_t *reply);

       int xcb_get_property_value_length(const xcb_get_property_reply_t *reply);

       xcb_generic_iterator_t xcb_get_property_value_end(const xcb_get_property_reply_t *reply);

REQUEST ARGUMENTS

       conn      The XCB connection to X11.

       _delete   Whether the property should actually be deleted. For deleting a property, the
                 specified type has to match the actual property type.

       window    The window whose property you want to get.

       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).

REPLY FIELDS

       response_type
                 The type of this reply, in this case XCB_GET_PROPERTY. 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).

       format    Specifies whether the data should be viewed as a list of 8-bit, 16-bit, or
                 32-bit quantities. Possible values are 8, 16, and 32. This information allows
                 the X server to correctly perform byte-swap operations as necessary.

       type      The actual type of the property (an atom).

       bytes_after
                 The number of bytes remaining to be read in the property if a partial read was
                 performed.

       value_len The length of value. You should use the corresponding accessor instead of this
                 field.

DESCRIPTION

       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?

RETURN VALUE

       Returns an xcb_get_property_cookie_t. Errors have to be handled when calling the reply
       function xcb_get_property_reply.

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

ERRORS

       xcb_atom_error_t
                 property or type do not refer to a valid atom.

       xcb_value_error_t
                 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).

       xcb_window_error_t
                 The specified window does not exist.

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);
       }

SEE ALSO

       xcb-requests(3), xcb-examples(3), xcb_intern_atom(3), xprop(1)

AUTHOR

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