[GHC] #14810: Define MVar "This function is atomic only if there are no other producers for this MVar."

[GHC]

#14810: Define MVar "This function is atomic only if there are no other producers
for this MVar."
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        Reporter:  akfp              |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  libraries/base    |              Version:  8.2.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Documentation     |  Unknown/Multiple
  bug                                |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by akfp):

 The sentence might need to link to the section:

 "In particular, the "bigger" functions in this module (readMVar, swapMVar,
 withMVar, modifyMVar_ and modifyMVar) are simply the composition of a
 takeMVar followed by a putMVar with exception safety. These only have
 atomicity guarantees if all other threads perform a takeMVar before a
 putMVar as well; otherwise, they may block."

 or that section needs to define "producer".

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14810#comment:1>
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