When you move from regular Perl to Tk, you have to adjust to the idea of the "event loop" in Tk. You don't want to setup anything to "block" it's flow. Typically you use Tk::after to check something on a time interval,and move on. In your case, the socket is blocking and one solution is to use IO::Select. But Tk has a built in feature to do this called Tk::fileevent.

How do I poll for input - as in:

while ($msg = <STDIN>) {}
while ($sock->recv($msg)) {}

Look up "Tk::fileevent":

      Tk::fileevent - Execute a callback when a filehandle
      becomes readable or writable

SYNOPSIS
      $widget->fileevent(fileHandle,readable?,callback?)

      $widget->fileevent(fileHandle,writable?,callback?)

DESCRIPTION
      This command is used to create file event handlers.  A
      file event handler is a binding between a filehandle and a
      callback, such that the callback is evaluated whenever the
      filehandle becomes readable or writable.  File event han
      dlers are most commonly used to allow data to be received
      from another process on an event-driven basis, so that the
      receiver can continue to interact with the user while