[Haskell-cafe] lazy strings and parallel read

Manlio Perillo manlio_perillo at libero.it
Fri Sep 19 13:50:11 EDT 2008

Duncan Coutts ha scritto:
> On Fri, 2008-09-19 at 18:46 +0200, Manlio Perillo wrote:
>> Don Stewart ha scritto:
>>> manlio_perillo:
>>>> Hi.
>>>> After having read
>>>> http://book.realworldhaskell.org/read/concurrent-and-multicore-programming.html#id676390
>>>> I have a doubt about Data.ByteString.Lazy.
>>>> Why getContents function don't use pread (or an emulation, if not 
>>>> available)?
>>> Why would it?
>> So that you don't need to open the same file multiple time:
>> http://book.realworldhaskell.org/read/concurrent-and-multicore-programming.html#id677193
> We are constrained here by the semantics of Handle which requires
> that getContents semi-close the Handle (which in turn is to make it
> harder to shoot yourself in the foot while doing lazy IO).

But if every function that reads the data uses pread, then this should 
no more be a problem.

Or I'm missing some other thing?

> Duncan

Manlio Perillo

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