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phicarre
Posted: Fri Mar 27, 2009 4:44 pm Reply with quote
User Joined: 23 Mar 2009 Posts: 14
which is the difference between the following instructions ?
spawn(?module,process(arguments))
spawn(?module,process,[arguments])

The second one gives me a compilation error: process is unused and a run-time error: error in process P on node N with exit value: {undef,[{module,process,[...]}]}


Last edited by phicarre on Fri Mar 27, 2009 5:17 pm; edited 1 time in total
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keymone
Posted: Fri Mar 27, 2009 4:56 pm Reply with quote
User Joined: 17 Sep 2007 Posts: 11 Location: Lviv, Ukraine
spawn(?MODULE, process(Arguments)) - this is wrong, you probably want to do this:

spawn(?MODULE, process, [Arguments]) - this is correct spawn call but you need to export process function:

-export([process/number_of_arguments]).

the error you get is actually a warning and it means you defined process function but never exported it.
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phicarre
Posted: Fri Mar 27, 2009 10:45 pm Reply with quote
User Joined: 23 Mar 2009 Posts: 14
But that runs !
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keymone
Posted: Mon Mar 30, 2009 6:32 am Reply with quote
User Joined: 17 Sep 2007 Posts: 11 Location: Lviv, Ukraine
there is only 1 definition of spawn/2 described in documentation: http://www.erlang.org/doc/man/erlang.html#spawn-2

spawn(Node, Fun) -> pid()

in your case it means

?MODULE should return correct Node name and
process(Arguments) should return a fun

otherwise you'll run into runtime error

if it does runs you should provide some code because i have no idea how should it look like to make that spawn/2 work correctly
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