how do I use SO_USELOOPBACK?

[Flame Bait]

I'm writting codes which uses sockets to communicate between various
processes both on my local machine and other machines.  It seems to
take the same length of time to communicate with processes on a local
machine as processes on some other machine, which surprises me.

While looking through sys/socket.h I found a socket option called
SO_USELOOPBACK, which looks like it is related to my problem. I
have these questions:

  Is the default to use loop back options when they are available?
  Or is the default not to unless the users specifies that loopback
  is wanted?  (That is is loopback already being used, with out my
  asking for it?)

  How can I use this option?  I know about setsockopt, but the documentation
  I have does not talk about SO_USELOOPBACK.  Can someone send me 
  some sample code?

  Will this speed things up?

All of this is running on Sun 3/60s with SunOS 3.something.  Email me
responces.  If there are enough, I'll make a mini-manual for looping
back, and post it.  Thanks.

Joshua Levy
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Addresses:                      a portable program.  No exceptions."  
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