A LispWorks client can set up an advise loop across a conversation using
dde-advise-start
, which takes a
conversation
(or a
service
designator/
topic
designator pair in the case of an automatically managed conversation using
dde-advise-start*
), an
item
, and a
key
as its main arguments. The
key
argument defaults to the conversation name, and can be used to distinguish between multiple advise loops established on the same service/topic/item group.
dde-advise-start conversation item &key key function format datap type
errorp
The
dde-advise-start
function sets up an advise loop for the data item specified by
item
on the specified
conversation
.
dde-client-advise-data
key
item
data
&key &allow-other-keys
The generic function
dde-client-advise-data
is the default function called when an advise loop informs a client that the data monitored by the loop has changed. By default it does nothing, but it may be specialized on the object used as the key in
dde-advise-start
or
dde-advise-start*
, or on a client conversation class if the default key is used.
define-dde-client
name
&key
service
class
The macro
define-dde-client
defines a mapping from the symbol
name
to the DDE service name with which to establish a conversation, and the conversation class to use for this conversation. The argument
service
is a string which names the DDE service. It defaults to the print-name of
name
. The argument
class
is a subclass of
dde-client-conversation
which is used for all conversations with this service. It defaults to
dde-client-conversation
. Specifying a subclass allows various aspects of the behavior of the conversation to be specialized.
The following is an example of how to set up an advise loop. The first step defines a client conversation class, called
my-conv
.
(defclass my-conv (dde-client-conversation)
())
The function
define-dde-client
can now be used to define a specific instance of the
my-conv
class for referring to a server application that responds to the service name "
FOO
".
(win32:define-dde-client :foo :service "FOO" :class my-conv)
The next step defines a method on
dde-client-advise-data
which returns a string stating that the item has changed.
(defmethod dde-client-advise-data ((self my-conv) item data &key
&allow-other-keys)
(format t "~&Item ~s changed to ~s~%" item data))
Finally, the next command starts the advise loop on the server
foo
, with the topic name "
file1
", to monitor the item "
slot1
".
(win32:dde-advise-start* :foo "file1" "slot1")
When the value of the item specified by "
slot1
"" changes, the server calls
dde-client-advise-data
which returns a string, as described above.
The
function
argument of
dde-advise-start
and
dde-advise-start*
specifies the function called by the advise loop when it notices a change to the item it is monitoring. The function is
dde-client-advise-start
by default. A different function can be provided, and should have a lambda list similar to the following:
key
item
data
&key
conversation
&allow-other-keys
The arguments
key
and
item
identify the advise loop, or link. The argument
data
contains the new data for hot links; for warm links it is
nil
.
Advise loops are closed using
dde-advise-stop
or
dde-advise-stop*
.
dde-advise-stop conversation item &key key format errorp
disconnectp no-advise-ok
The function
dde-advise-stop
removes a particular link from
conversation
specified by
item
,
format
and
key
. If
key
is the last key for the
item
/
format
pair, the advise loop for the pair is terminated.