1send(n) Tk Built-In Commands send(n)
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8 send - Execute a command in a different application
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11 send ?options? app cmd ?arg arg ...?
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16 This command arranges for cmd (and args) to be executed in the applica‐
17 tion named by app. It returns the result or error from that command
18 execution. App may be the name of any application whose main window is
19 on the display containing the sender's main window; it need not be
20 within the same process. If no arg arguments are present, then the
21 command to be executed is contained entirely within the cmd argument.
22 If one or more args are present, they are concatenated to form the com‐
23 mand to be executed, just as for the eval command.
24 If the initial arguments of the command begin with “-” they are treated
26 as options. The following options are currently defined:
27 -async Requests asynchronous invocation. In this case the send command
29 will complete immediately without waiting for cmd to complete in
30 the target application; no result will be available and errors
31 in the sent command will be ignored. If the target application
32 is in the same process as the sending application then the
33 -async option is ignored.
34 -displayof pathName
36 Specifies that the target application's main window is on the
37 display of the window given by pathName, instead of the display
38 containing the application's main window.
39 -- Serves no purpose except to terminate the list of options. This
41 option is needed only if app could contain a leading “-” charac‐
42 ter.
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46 The name of an application is set initially from the name of the pro‐
47 gram or script that created the application. You can query and change
48 the name of an application with the tk appname command.
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52 If the send command is removed from an application (e.g. with the com‐
53 mand rename send {}) then the application will not respond to incoming
54 send requests anymore, nor will it be able to issue outgoing requests.
55 Communication can be reenabled by invoking the tk appname command.
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59 The send command is potentially a serious security loophole. On Unix,
60 any application that can connect to your X server can send scripts to
61 your applications. These incoming scripts can use Tcl to read and
62 write your files and invoke subprocesses under your name. Host-based
63 access control such as that provided by xhost is particularly insecure,
64 since it allows anyone with an account on particular hosts to connect
65 to your server, and if disabled it allows anyone anywhere to connect to
66 your server. In order to provide at least a small amount of security,
67 Tk checks the access control being used by the server and rejects
68 incoming sends unless (a) xhost-style access control is enabled (i.e.
69 only certain hosts can establish connections) and (b) the list of
70 enabled hosts is empty. This means that applications cannot connect to
71 your server unless they use some other form of authorization such as
72 that provide by xauth. Under Windows, send is currently disabled.
73 Most of the functionality is provided by the dde command instead.
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76 This script fragment can be used to make an application that only runs
77 once on a particular display.
78 if {[tk appname FoobarApp] ne "FoobarApp"} {
79 send -async FoobarApp RemoteStart $argv
80 exit
81 }
82 # The command that will be called remotely, which raises
83 # the application main window and opens the requested files
84 proc RemoteStart args {
85 raise .
86 foreach filename $args {
87 OpenFile $filename
88 }
89 }
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92 application, dde, name, remote execution, security, send
93Tk 4.0 send(n)