Comment from Net::Wire10 source code:

  # If select() said data is available, but it
  # was not, it means the connection was lost.
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I interpret this to be that IO::Select on a blocking socket will falsely return "data available" if the OS TCP socket is in one of the disconnected states.

Another comment:

  # IO::Select sometimes returns undef
  # instead of an empty array.
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So beware of that..

And a third one about alarm() and can_read():

  Alarms are silently cancelled after
  IO::Select->can_read() is called.
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Of course, $SIG{ALRM} and signals in general is usually busted in many other ways, so you probably avoid a lot of trouble by steering clear of signals completely, making this less of an issue. Net::Wire10 uses threads::shared and a shared instance variable for signaling.