$DECLARE 'KCMLDdeOpen(STR(), STR())

This function attempts to open a DDE conversation with another Windows application, and if successful, returns a conversation handle - basically a unique number that identifies this particular DDE conversation. The name of the application (app$) and the topic to converse on (topic$) are passed to this function. Applications that support DDE in server mode can accept data on numerous different 'topics' - a logical way of splitting up DDE requests into groups. Most DDE server applications support the 'system' topic, and can even supply a list of supported topics (and help text on each one) to a client application.

Even though DDE is a standard way for Windows applications to communicate, once the link is established, the standards quickly disappear. Each DDE server application expects commands in different formats. For example, controlling Excel via a DDE link involves executing commands from the Excel macro language, whereas to control Word for Windows requires using WordBasic commands.

Programs should make a call to KCMLDdeLoad prior to making this call, to make sure that the DDE server application is loaded. Once a conversation is no longer needed, an application should call the KCMLDdeClose function.

Example

The following code will open a DDE conversation with the Windows Program Manager. Note that this program supports a general topic called 'progman'.

ret = 'KCMLDdeInit()
IF (ret != 0)
  dde = 'KCMLDdeOpen("progman", "progman")
  IF (dde != 0)
    PRINT "Conversation established OK"
    'KCMLDdeClose(dde)
  END IF
  'KCMLDdeDestroy()
END IF