Manual Pages for UNIX Operating System command usage for man dde

Tcl Bundled Packages                                      dde(1T)



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NAME
     dde - Execute a Dynamic Data Exchange command

SYNOPSIS
     package require dde 1.2

     dde eval ?-async? service cmd ?arg ...?

     dde execute ?-async? service topic data

     dde poke service topic item data

     dde request ?-binary? service topic data

     dde servername ?topic?

     dde services service topic
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DESCRIPTION
     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;  Tcl uses the service name TclEval, while the topic
     name is the name of the interpreter given by dde servername.
     Other  applications have their own service names and topics.
     For instance, Microsoft Excel has the service name Excel.

     The eval and execute commands accept the option -async:


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

     dde servername ?topic?
          dde servername  registers  the  interpreter  as  a  DDE
          server with the service name TclEval and the topic name
          specified by topic.  If no topic is given, dde  server-
          name returns the name of the current topic or the empty
          string if it is not registered as a service.

     dde execute ?-async? 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



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Tcl Bundled Packages                                      dde(1T)



          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.

     dde poke service topic item data
          dde poke 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 appli-
          cation  specific  but can be a command to the server or
          the name of a file to work on.  The item is also appli-
          cation  specific  and  is  often  not used, but it must
          always be non-null.  The data field  is  given  to  the
          remote application.

     dde request ?-binary? service topic item
          dde request is typically used to get the value of some-
          thing;  the  value  of a cell in Microsoft Excel or the
          text of a selection in Microsoft Word. service is typi-
          cally  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.

     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.

     dde eval ?-async? topic cmd ?arg arg ...?
          dde eval 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.





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Tcl Bundled Packages                                      dde(1T)



DDE AND TCL
     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  dde  servername.
     Each interp is available as a DDE topic only if the dde ser-
     vername command was used to set the name of  the  topic  for
     each  interp.  So  a  dde  services  TclEval {} command will
     return a list of service-topic  pairs,  where  each  of  the
     currently running interps will be a topic.

     When Tcl 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 Tcl processes a dde request  command,  it  returns  the
     value  of  the variable given in the dde command in the con-
     text of the interp named by the dde topic. Tcl reserves  the
     variable  $TCLEVAL$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  Tcl
     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.

     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.


EXAMPLE
     This asks Internet Explorer (which must already be  running)
     to go to a particularly important website:
          package require dde
          dde execute iexplore WWW_OpenURL http://www.tcl.tk/


SEE ALSO
     tk(1T), winfo(1T), send(1T)


KEYWORDS
     application, dde, name, remote execution

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



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Tcl Bundled Packages                                      dde(1T)



     _______________________________________
    |   ATTRIBUTE TYPE   |  ATTRIBUTE VALUE|
    |____________________|__________________|_
    | Availability       |  runtime/tcl-8  |
    |____________________|__________________|_
    | Interface Stability|  Uncommitted    |
    |____________________|_________________|

NOTES
     Source for Tcl is available on http://opensolaris.org.













































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