Provided by: tk8.4-doc_8.4.19-4_all bug

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.  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                                   │