dde - Execute a Dynamic Data Exchange command

       A Tcl interpreter always has a service name of TclEval.  Each different interpreter of  all  running  Tcl
       applications  must  be given a unique name specified by ddeservername. Each interp is available as a DDE
       topic only if the ddeservername command was used to set the name of the topic for each interp. So a  ddeservicesTclEval{}  command  will  return  a  list of service-topic pairs, where each of the currently
       running interps will be a topic.

       When Tcl processes a ddeexecute command, the data for the execute is run as a script in the interp named
       by the topic of the ddeexecute command.

       When Tcl processes a dderequest command, it returns the value of the variable given in the  dde  command
       in  the  context  of the interp named by the dde topic. Tcl reserves the variable $TCLEVAL$EXECUTE$RESULT
       for internal use, and dderequest commands for that variable will give unpredictable results.

       An external application which wishes to run a script in Tcl should have that script store its result in a
       variable, run the ddeexecute command, and then run dderequest to get the value of the variable.

       When using DDE, be careful to ensure that the event queue is flushed using either update or vwait.   This
       happens by default when using wish unless a blocking command is called (such as exec without adding the &
       to  place the process in the background).  If for any reason the event queue is not flushed, DDE commands
       may hang until the event queue is flushed.  This can create a deadlock situation.

       The following commands are a subset of the full Dynamic Data Exchange set of commands.

       ddeservername ?-force? ?-handlerproc? ?--? ?topic?
              ddeservername  registers  the  interpreter as a DDE server with the service name TclEval and the
              topic name specified by topic.  If no topic is given, ddeservername  returns  the  name  of  the
              current topic or the empty string if it is not registered as a service. If the given topic name is
              already  in  use,  then  a  suffix  of  the form “ #2” or “ #3” is appended to the name to make it
              unique. The command's result will be the name actually used. The -force option is  used  to  force
              registration of precisely the given topic name.

              The  -handler  option  specifies  a  Tcl procedure that will be called to process calls to the dde
              server. If the package has been loaded into a safe interpreter then a -handler procedure  must  be
              defined. The procedure is called with all the arguments provided by the remote call.

       ddeexecute ?-async? ?-binary? servicetopicdataddeexecute  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  -async  option  requests
              asynchronous  invocation.   The command returns an error message if the script did not run, unless
              the -async flag was used, in which case the command returns immediately with no error.

              Without the -binary option all data will be sent in unicode. For dde clients which don't implement
              the CF_UNICODE clipboard format, this will automatically be translated to the system encoding. You
              can use the -binary option in combination with the result of encodingconvertto to  send  data  in
              any other encoding.

       ddepoke ?-binary? servicetopicitemdataddepoke  passes  the data to the server indicated by service using the topic and item specified.
              Typically, service is the name of an application.  topic is application  specific  but  can  be  a
              command to the server or the name of a file to work on.  The item is also application specific and
              is  often  not  used,  but  it  must  always  be  non-null.  The data field is given to the remote
              application.

              Without the -binary option all data will be sent in unicode. For dde clients which don't implement
              the CF_UNICODE clipboard format, this will automatically be translated to the system encoding. You
              can use the -binary option in combination with the result of encodingconvertto to  send  data  in
              any other encoding.

       dderequest ?-binary? servicetopicitemdderequest  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.  Normally this is interpreted  to
              be  a  string  with  terminating  null.  If -binary is specified, the result is returned as a byte
              array.

       ddeservicesservicetopicddeservices returns a list of service-topic pairs that currently exist on the machine. If service
              and topic are both empty strings ({}), then all service-topic pairs  currently  available  on  the
              system  are  returned.  If service is empty and topic is not, then all services with the specified
              topic are returned. If service is non-empty and topic is, all  topics  for  a  given  service  are
              returned.  If  both  are  non-empty,  if that service-topic pair currently exists, it is returned;
              otherwise, an empty string is returned.

       ddeeval ?-async? topiccmd ?argarg...?
              ddeeval evaluates a command and its arguments using the interpreter specified by topic.  The  DDE
              service  must  be  the  TclEval service.  The -async option requests asynchronous invocation.  The
              command returns an error message if the script did not run, unless the -async flag  was  used,  in
              which  case  the  command  returns immediately with no error.  This command can be used to replace
              send on Windows.

       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  servicename  and  a  topic. Both the servicename and topic are application
       defined; Tcl uses the service name TclEval, while the topic name is the name of the interpreter given  by
       ddeservername. Other applications have their own servicenames and topics. For instance, Microsoft Excel
       has the service name Excel.

       This asks Internet Explorer (which must already be running) to go to a particularly important website:

              package require dde
              ddeexecute -async iexplore WWW_OpenURL http://www.tcl-lang.org/

       application, dde, name, remote execution

dde                                                    1.4                                             dde(3tcl)

       dde - Execute a Dynamic Data Exchange command

tk(3tk), winfo(3tk), send(3tk)

packagerequiredde1.4ddeservername ?-force? ?-handlerproc? ?--? ?topic?
       ddeexecute ?-async? ?-binary? servicetopicdataddepoke ?-binary? servicetopicitemdatadderequest ?-binary? servicetopicitemddeservicesservicetopicddeeval ?-async? topiccmd ?argarg...?
________________________________________________________________________________________________________________