> Your code is broken in a most evil and insidious way.

 

Interesting.  This is for a toy project, so I'm not too worried, but lets say I wanted to do this "correctly" and I was set on using IOUArray for some reason. (The Haskell wiki claims that StorableArray is slower; is that actually the case?)

 

Which of the following fixes would work now?  Which has the lowest probability of not working in the future?

 

1) Declare f to take Addr# and don't construct a Ptr Word32

    I suspect this would be enough unless the GC changed to some sort of continous GC which can happen even without an allocation

 

2) Declare f to take MutableByteArray#

    Is this good enough to make the collector happy?

 

3) Something else I haven't thought of?

 

If there was no other option, and StorableArray wasn't slower, and I was working on a real project, I'd probably wrap my own around ForeignPtr like Data.ByteString.

 

  -- ryan