Tk Built-In Commands                                     send(1T)





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 contain-
     ing 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 con-
     catenated 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  win-
          dow.

     --   Serves no purpose  except  to  terminate  the  list  of
          options.   This option is needed only if app could con-
          tain a leading ``-'' character.


APLICATION 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.




Tk                      Last change: 4.0                        1






Tk Built-In Commands                                     send(1T)



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 con-
     trol 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      

ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:





Tk                      Last change: 4.0                        2






Tk Built-In Commands                                     send(1T)



     
       ATRIBUTE TYPE     ATRIBUTE VALUE
    
     Availability         SUNWTk         
    
     Interface Stability  Uncommitted    
    

NOTES
     Source for Tk is available on http:/opensolaris.org.













































Tk                      Last change: 4.0                        3