Provided by: tk8.6-doc_8.6.8-4_all 
NAME
send - Execute a command in a different application
SYNOPSIS
send ?options? app cmd ?arg arg ...? ________________________________________________________________________________________________________________
DESCRIPTION
This command arranges for cmd (and args) to be executed in the application named by app. It returns the
result or error from that command execution. App may be the name of any application whose main window is
on the display containing the sender's main window; it need not be within the same process. If no arg
arguments are present, then the command to be executed is contained entirely within the cmd argument. If
one or more args are present, they are concatenated to form the command to be executed, just as for the
eval command.
If the initial arguments of the command begin with “-” they are treated as options. The following
options are currently defined:
-async Requests asynchronous invocation. In this case the send command will complete immediately without
waiting for cmd to complete in the target application; no result will be available and errors in
the sent command will be ignored. If the target application is in the same process as the sending
application then the -async option is ignored.
-displayof pathName
Specifies that the target application's main window is on the display of the window given by
pathName, instead of the display containing the application's main window.
-- Serves no purpose except to terminate the list of options. This option is needed only if app
could contain a leading “-” character.
APPLICATION NAMES
The name of an application is set initially from the name of the program or script that created the
application. You can query and change the name of an application with the tk appname command.
DISABLING SENDS
If the send command is removed from an application (e.g. with the command rename send {}) then the
application will not respond to incoming send requests anymore, nor will it be able to issue outgoing
requests. Communication can be reenabled by invoking the tk appname command.
SECURITY
The send command is potentially a serious security loophole. On Unix, any application that can connect to
your X server can send scripts to your applications. These incoming scripts can use Tcl to read and
write your files and invoke subprocesses under your name. Host-based access control such as that
provided by xhost is particularly insecure, since it allows anyone with an account on particular hosts to
connect to your server, and if disabled it allows anyone anywhere to connect to your server. In order to
provide at least a small amount of security, Tk checks the access control being used by the server and
rejects incoming sends unless (a) xhost-style access control is enabled (i.e. only certain hosts can
establish connections) and (b) the list of enabled hosts is empty. This means that applications cannot
connect to your server unless they use some other form of authorization such as that provide by xauth.
Under Windows, send is currently disabled. Most of the functionality is provided by the dde command
instead.
EXAMPLE
This script fragment can be used to make an application that only runs once on a particular display.
if {[tk appname FoobarApp] ne "FoobarApp"} {
send -async FoobarApp RemoteStart $argv
exit
}
# The command that will be called remotely, which raises
# the application main window and opens the requested files
proc RemoteStart args {
raise .
foreach filename $args {
OpenFile $filename
}
}
KEYWORDS
application, dde, name, remote execution, security, send