multiple instances of standalone under Windows

[Dar Scott]

On Friday, January 30, 2004, at 09:13 AM, Chris Sheffield wrote:

> Thanks for the suggestions, Dar, but I think maybe not understand the
> 'accept' thing.  It sounds like it should work, but I'm not quite 
> getting
> it.  You don't by chance have a code sample do you?  How will I know 
> if the
> accept command fails?

Off the top of my head:

********************************
constant lockPort = "46144"


function lockApp  -- returns true iff OK to continue running
   accept datagram connections on port lockPort with message 
closeRightAway
   return the result is empty
end lockApp

function unlockApp
   close socket lockPort
end unlockApp

on closeRightAway socketID, data
   close socket socketId
end closeRightAway

*********************************

The system should close the listening port when the app quits, but you 
might want to put the unlockApp in all the right places, anyway.

The specific message on OS X when the port is busy is "can't bind 
endpoint", but I have noticed that messages do not always line up 
between systems.  You can also check the syserr() to get the OS error 
code if you want to make sure the exact reason of failure is because 
there is another app using the port and not because the networking is 
broken or something.

Dar Scott
-- 
****************************************
     Dar Scott Consulting
     http://www.swcp.com/dsc/
     Programming Services
****************************************