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 exam‐
       ple 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-re‐
       quests(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.

X Version 11                                       libxcb 1.15                               xcb_get_property(3)