[MacRuby-devel] [MacRuby] #597: Dispatch Queue async method inconsistent results

[MacRuby]

#597: Dispatch Queue async method inconsistent results
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 Reporter:  Knut.Olaf.Lien@…          |        Owner:  ernest.prabhakar@…        
     Type:  defect                    |       Status:  closed                    
 Priority:  blocker                   |    Milestone:                            
Component:  MacRuby                   |   Resolution:  invalid                   
 Keywords:  GCD async method          |  
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Changes (by ernest.prabhakar@…):

  * status:  new => closed
  * resolution:  => invalid


Comment:

 I even get it with no function at all.
 => [0, 1, 2, 3, false, 5]

 Oh, wait,  you're using a *local* variable.  You  need to use a block
 variable, I think:

 @result = []; 8.times {|i| q.async(grp) {@result[i] = i}}

 p @result => [0, 1, 2, 3, 4, 5, 6, 7]

 Using a copy of the array "sometimes" works, but I'm not quite sure how or
 why.  Still, the technical answer is that attempting to modify a dynamic
 object inside a GCD leads to "undefined"  behavior, so I'll mark this as
 "behaves correctly". :-/

-- 
Ticket URL: <http://www.macruby.org/trac/ticket/597#comment:3>
MacRuby <http://macruby.org/>