[erlang-questions] Why should sending sometimes fail

Johan Montelius <>
Mon Mar 1 12:26:07 CET 2010


I guessed that the question had been raised before. I understand that  
changing things now would make many programs suspend waiting for a reply  
that will never come. We can have it in mind for Erlang2 though.

The monitors I do like (as opposed to link/1 that also has this  
"optimization" of throwing exceptions). One thing I would like to see  
however is that a monitor could produce two different messages depending  
on if the death is certain or not.

A {'DOWN', Ref, process, Pid, noconnection} is not really the same as the  
other messages. The process could be alive and you could even receive  
messages from it if there was a temporary network problem. To make this  
more visible one could (I know not now but in Erlang2) be given a message  
of its own:

{'SUSPECTED', Ref, process, Pid, noconnection}

When building replicated servers there is a big difference between knowing  
and suspecting.

  Johan




-- 
Dr Johan Montelius
Royal Institute of Technology - KTH
School of Information and Communication Technology - ICT


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