- NAME
- dde - Execute a Dynamic Data Exchange command
- SYNOPSIS
- dde ?-async? command service topic ?data?
- DESCRIPTION
- -async
- DDE COMMANDS
- dde execute service topic data
- dde request service topic item
- dde services service topic
- DDE AND TK
- KEYWORDS
- SEE ALSO
dde - Execute a Dynamic Data Exchange command
dde ?-async? command service topic ?data?
This command allows an application to send Dynamic Data Exchange (DDE)
command when running under Microsoft Windows. Dynamic Data Exchange is
a mechanism where applications can exchange raw data. Each DDE
transaction needs a service name and a topic. Both the
service name and topic are application defined; Tk uses
the service name Tk, while the topic name is the name of the
interpreter given by tk appname. Other applications have their
own service names and topics. For instance, Microsoft Excel
has the service name Excel.
The only option to the send command is:
- -async
-
Requests asynchronous invocation. This is valid only for the
execute subcommand. Normally, the dde execute subcommand
waits until the command completes, returning appropriate error
messages. When the -async option is used, the command returns
immediately, and no error information is available.
The following commands are a subset of the full Dynamic Data Exchange
set of commands.
- dde execute service topic data
-
dde execute takes the data and sends it to the server
indicated by service with the topic indicated by
topic. Typically, service is the name of an application,
and topic is a file to work on. The data field is given
to the remote application. Typically, the application treats the
data field as a script, and the script is run in the
application. The command returns an error if the script did not
run. If the -async flag was used, the command
returns immediately with no error.
- dde request service topic item
-
dde request is typically used to get the value of something; the
value of a cell in Microsoft Excel or the text of a selection in
Microsoft Word. service is typically the name of an application,
topic is typically the name of the file, and item is
application-specific. The command returns the value of item as
defined in the application.
- dde services service topic
-
dde services returns a list of service-topic pairs that
currently exist on the machine. If service and topic are
both null strings ({}), then all service-topic pairs currently
available on the system are returned. If service is null and
topic is not, then all services with the specified topic are
returned. If service is not null and topic is, all topics
for a given service are returned. If both are not null, if that
service-topic pair currently exists, it is returned; otherwise, null
is returned.
Tk always has a service name of "Tk". Each different interp of all
running Tk applications has a unique name. A list of running interps
can be retrieved using the winfo interps command. A given
interp's name can be set with the tk appname. Each interp is
available as a DDE topic. So a dde services Tk {} command will
return a list of service-topic pairs, where each of the currently
running interps will be a topic.
When Tk processes a dde execute command, the data for the
execute is run as a script in the interp named by the topic of the
dde execute command.
When Tk processes a dde request command, it returns the value of
the variable given in the dde command in the context of the interp
named by the dde topic. Tk reserves the variable "$TK$EXECUTE$RESULT"
for internal use, and dde request commands for that variable
will give unpredictable results.
An external application which wishes to run a script in Tk should have
that script store its result in a variable, run the dde execute
command, and the run dde request to get the value of the
variable.
application, dde, name, remote execution
tk, winfo, send
Copyright © 1997 Sun Microsystems, Inc.
Copyright © 1995-1997 Roger E. Critchlow Jr.