NAME

       send - Execute a command in a different application

SYNOPSIS

       send ?options? app cmd ?arg arg ...?
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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. 2
       Under  Windows,  send  is  currently  disabled.  Most of the functionality is provided by the dde command 2
       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                                                  2

Tk                                                     4.0                                             send(3tk)