Uncertain death

Ulf Wiger (AL/EAB) <>
Sun Nov 20 15:45:14 CET 2005


I agree.  /Uffe


________________________________

	From: Robert Virding [mailto:] 
	Sent: den 19 november 2005 18:21
	To: Ulf Wiger (AL/EAB)
	Cc: Dominic Williams; 
	Subject: Re: Uncertain death
	
	
	Doing exit(Pid, kill) sends an exit signal, of value kill, to
the process so it should be scheduled in the same way as "normal" exit
signals. Generally I think you should be careful if you start special
casing various things as you can get unexpected behavious.
	
	Robert
	
	Ulf Wiger (AL/EAB) wrote: 

		When you send an exit signal to a process,
		it is scheduled in order to receive it.
		This goes for 'kill' messages as well, even
		though you'd think that they could be 
		killed right away by the runtime system.
		
		/Uffe
		
		  

			-----Original Message-----
			From:  
			[mailto:] On
Behalf Of 
			Dominic Williams
			Sent: den 17 november 2005 23:32
			To: ''
			Subject: Uncertain death
			
			Hello,
			
			The following program seems to me to indicate
that when a 
			processes gets killed, there is, for a brief
moment, 
			contradictory information about its state.
Specifically, the 
			information returned by processes() seems to lag
behind that 
			given by is_process_alive().
			
			
			%%% death.erl
			
			-module (death).
			-export ([run/0, server/0]).
			
			run() ->
			     Pid = spawn (?MODULE, server, []),
			     exit (Pid, kill),
			     report (Pid),
			     timer:sleep(1000),
			     report (Pid).
			
			report (Pid) ->
			     io:fwrite("~p alive: ~p; member of
processes(): ~p~n",
			               [Pid, is_process_alive (Pid),
			                lists:member(Pid,
processes())]).
			
			server () ->
			     receive
			         hello ->
			             server();
			         stop ->
			             bye
			     end.
			
			%%% end death.erl
			
			1> c("/Users/dodo/tmp/death", [{outdir,
"/Users/dodo/tmp/"}]).
			{ok,death}
			2> death:run().
			<0.35.0> alive: false; member of processes():
true <0.35.0> 
			alive: false; member of processes(): false ok
			
			Same result under MacOS/R9C and WinXP/R10B
			
			Regards,
			
			Dominic Williams
			http://www.dominicwilliams.net
			
			----
			
			    

		
		  

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