Documentation in Control.Monad.STM.TMVar - isEmptyTMVar

[Heinrich Apfelmus]

Hello,

As of  stm-2.2.0.1, the documentation for the  isEmptyTMVar  function 
[1] reads

   isEmptyTMVar :: TMVar a -> STM BoolSource

   Check whether a given TMVar is empty.

   Notice that the boolean value returned is just a snapshot of the state
   of the TMVar. By the time you get to react on its result, the TMVar
   may have been filled (or emptied) - so be extremely careful when using
   this operation. Use tryTakeTMVar instead if possible.

This being software transactional memory, where everything is wrapped 
into a call to the  atomically  function, I believe that the second 
paragraph is now completely obsolete, to the point of being misleading 
(it sure scared me). I would be relieved if someone could remove it. 
Most likely, it was originally copied directly from the corresponding 
documentation of  Control.Concurrent.MVar .


   [1]: 
http://hackage.haskell.org/packages/archive/stm/2.2.0.1/doc/html/Control-Concurrent-STM-TMVar.html#v:isEmptyTMVar


Best regards,
Heinrich Apfelmus

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