190 lines
8.0 KiB
Plaintext
190 lines
8.0 KiB
Plaintext
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'\"
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'\" Copyright (c) 1997 Sun Microsystems, Inc.
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'\" Copyright (c) 2001 ActiveState Corporation.
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'\"
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'\" See the file "license.terms" for information on usage and redistribution
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'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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'\"
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.TH dde n 1.4 dde "Tcl Bundled Packages"
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.so man.macros
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.BS
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'\" Note: do not modify the .SH NAME line immediately below!
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.SH NAME
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dde \- Execute a Dynamic Data Exchange command
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.SH SYNOPSIS
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.sp
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\fBpackage require dde 1.4\fR
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.sp
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\fBdde servername\fR ?\fB\-force\fR? ?\fB\-handler \fIproc\fR? ?\fB\-\|\-\fR? ?\fItopic\fR?
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.sp
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.VS 8.6
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\fBdde execute\fR ?\fB\-async\fR? ?\fB\-binary\fR? \fIservice topic data\fR
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.sp
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\fBdde poke\fR ?\fB\-binary\fR? \fIservice topic item data\fR
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.VE 8.6
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.sp
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\fBdde request\fR ?\fB\-binary\fR? \fIservice topic item\fR
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.sp
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\fBdde services \fIservice topic\fR
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.sp
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\fBdde eval\fR ?\fB\-async\fR? \fItopic cmd \fR?\fIarg arg ...\fR?
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.BE
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.SH DESCRIPTION
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.PP
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This command allows an application to send Dynamic Data Exchange (DDE)
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command when running under Microsoft Windows. Dynamic Data Exchange is
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a mechanism where applications can exchange raw data. Each DDE
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transaction needs a \fIservice name\fR and a \fItopic\fR. Both the
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\fIservice name\fR and \fItopic\fR are application defined; Tcl uses
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the service name \fBTclEval\fR, while the topic name is the name of the
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interpreter given by \fBdde servername\fR. Other applications have their
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own \fIservice names\fR and \fItopics\fR. For instance, Microsoft Excel
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has the service name \fBExcel\fR.
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.PP
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.SH "DDE COMMANDS"
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.PP
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The following commands are a subset of the full Dynamic Data Exchange
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set of commands.
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.TP
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\fBdde servername \fR?\fB\-force\fR? ?\fB\-handler \fIproc\fR? ?\fB\-\|\-\fR? ?\fItopic\fR?
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.
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\fBdde servername\fR registers the interpreter as a DDE server with
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the service name \fBTclEval\fR and the topic name specified by \fItopic\fR.
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If no \fItopic\fR is given, \fBdde servername\fR returns the name
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of the current topic or the empty string if it is not registered as a
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service. If the given \fItopic\fR name is already in use, then a
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suffix of the form
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.QW " #2"
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or
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.QW " #3"
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is appended to the name to make it
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unique. The command's result will be the name actually used. The
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\fB\-force\fR option is used to force registration of precisely the
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given \fItopic\fR name.
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.RS
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.PP
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The \fB\-handler\fR option specifies a Tcl procedure that will be called to
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process calls to the dde server. If the package has been loaded into a
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safe interpreter then a \fB\-handler\fR procedure must be defined. The
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procedure is called with all the arguments provided by the remote
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call.
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.RE
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.TP
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\fBdde execute\fR ?\fB\-async\fR? ?\fB\-binary\fR? \fIservice topic data\fR
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.
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\fBdde execute\fR takes the \fIdata\fR and sends it to the server indicated
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by \fIservice\fR with the topic indicated by \fItopic\fR. Typically,
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\fIservice\fR is the name of an application, and \fItopic\fR is a file to
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work on. The \fIdata\fR field is given to the remote application.
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Typically, the application treats the \fIdata\fR field as a script, and the
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script is run in the application. The \fB\-async\fR option requests
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asynchronous invocation. The command returns an error message if the
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script did not run, unless the \fB\-async\fR flag was used, in which case
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the command returns immediately with no error.
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.VS 8.6
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Without the \fB\-binary\fR option all data will be sent in unicode. For
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dde clients which don't implement the CF_UNICODE clipboard format, this
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will automatically be translated to the system encoding. You can use
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the \fB\-binary\fR option in combination with the result of
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\fBencoding convertto\fR to send data in any other encoding.
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.VE 8.6
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.TP
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\fBdde poke\fR ?\fB\-binary\fR? \fIservice topic item data\fR
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.
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\fBdde poke\fR passes the \fIdata\fR to the server indicated by
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\fIservice\fR using the \fItopic\fR and \fIitem\fR specified. Typically,
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\fIservice\fR is the name of an application. \fItopic\fR is application
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specific but can be a command to the server or the name of a file to work
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on. The \fIitem\fR is also application specific and is often not used, but
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it must always be non-null. The \fIdata\fR field is given to the remote
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application.
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.VS 8.6
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Without the \fB\-binary\fR option all data will be sent in unicode. For
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dde clients which don't implement the CF_UNICODE clipboard format, this
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will automatically be translated to the system encoding. You can use
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the \fB\-binary\fR option in combination with the result of
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\fBencoding convertto\fR to send data in any other encoding.
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.VE 8.6
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.TP
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\fBdde request\fR ?\fB\-binary\fR? \fIservice topic item\fR
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.
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\fBdde request\fR is typically used to get the value of something; the
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value of a cell in Microsoft Excel or the text of a selection in
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Microsoft Word. \fIservice\fR is typically the name of an application,
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\fItopic\fR is typically the name of the file, and \fIitem\fR is
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application-specific. The command returns the value of \fIitem\fR as
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defined in the application. Normally this is interpreted to be a
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string with terminating null. If \fB\-binary\fR is specified, the
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result is returned as a byte array.
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.TP
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\fBdde services \fIservice topic\fR
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.
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\fBdde services\fR returns a list of service-topic pairs that
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currently exist on the machine. If \fIservice\fR and \fItopic\fR are
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both empty strings ({}), then all service-topic pairs currently
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available on the system are returned. If \fIservice\fR is empty and
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\fItopic\fR is not, then all services with the specified topic are
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returned. If \fIservice\fR is non-empty and \fItopic\fR is, all topics
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for a given service are returned. If both are non-empty, if that
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service-topic pair currently exists, it is returned; otherwise, an
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empty string is returned.
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.TP
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\fBdde eval\fR ?\fB\-async\fR? \fItopic cmd \fR?\fIarg arg ...\fR?
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.
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\fBdde eval\fR evaluates a command and its arguments using the interpreter
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specified by \fItopic\fR. The DDE service must be the \fBTclEval\fR
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service. The \fB\-async\fR option requests asynchronous invocation. The
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command returns an error message if the script did not run, unless the
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\fB\-async\fR flag was used, in which case the command returns immediately
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with no error. This command can be used to replace send on Windows.
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.SH "DDE AND TCL"
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.PP
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A Tcl interpreter always has a service name of \fBTclEval\fR. Each
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different interpreter of all running Tcl applications must be
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given a unique
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name specified by \fBdde servername\fR. Each interp is available as a
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DDE topic only if the \fBdde servername\fR command was used to set the
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name of the topic for each interp. So a \fBdde services TclEval {}\fR
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command will return a list of service-topic pairs, where each of the
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currently running interps will be a topic.
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.PP
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When Tcl processes a \fBdde execute\fR command, the data for the
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execute is run as a script in the interp named by the topic of the
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\fBdde execute\fR command.
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.PP
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When Tcl processes a \fBdde request\fR command, it returns the value of the
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variable given in the dde command in the context of the interp named by the
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dde topic. Tcl reserves the variable \fB$TCLEVAL$EXECUTE$RESULT\fR for
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internal use, and \fBdde request\fR commands for that variable will give
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unpredictable results.
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.PP
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An external application which wishes to run a script in Tcl should have
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that script store its result in a variable, run the \fBdde execute\fR
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command, and then run \fBdde request\fR to get the value of the
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variable.
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.PP
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When using DDE, be careful to ensure that the event queue is flushed
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using either \fBupdate\fR or \fBvwait\fR. This happens by default
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when using \fBwish\fR unless a blocking command is called (such as \fBexec\fR
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without adding the \fB&\fR to place the process in the background).
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If for any reason the event queue is not flushed, DDE commands may
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hang until the event queue is flushed. This can create a deadlock
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situation.
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.SH EXAMPLE
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.PP
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This asks Internet Explorer (which must already be running) to go to a
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particularly important website:
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.PP
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.CS
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package require dde
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\fBdde execute\fR -async iexplore WWW_OpenURL http://www.tcl-lang.org/
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.CE
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.SH "SEE ALSO"
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tk(n), winfo(n), send(n)
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.SH KEYWORDS
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application, dde, name, remote execution
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'\"Local Variables:
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'\"mode: nroff
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'\"End:
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