[Haskell-beginners] Named Pipes Et Cetera

[matthew coolbeth]

That's interesting.  This was using my source code?
On mine (also a Linux box), it exited immediately, giving me no
opportunity to write to the pipe.

On 2010-11-23, Patrick LeBoutillier <patrick.leboutillier at gmail.com> wrote:
> Matthew,
>
> Does it return immediately when you start it or only when you try to
> write to the pipe with some client?
>
> Here's what I get on my Linux box:
>
> $ rm /tmp/dld.fifo && ./pipe &
> [1] 8603
> $ echo -e "1\n2\n3" > /tmp/dld.fifo
> 1
> 2
> 3
> pipe: /tmp/dld.fifo: hGetLine: end of file
>
>
> Patrick
>
>
> On Tue, Nov 23, 2010 at 7:55 AM, matthew coolbeth
> <mac01021 at engr.uconn.edu> wrote:
>> Hello, all.
>>
>> Three questions:
>>
>> 1> What, if anything, can I do in a Haskell program to do blocking
>> reads from a Linux FIFO?  For the curious, there is a small program
>> below that doesn't block, but immediately terminates because of an EOF
>>
>> 2> How could I have found the answer to this question on my own? (The
>> documentation that Google found for me was not completely adequate)
>>
>> 3> Is this sort of question generally regarded as too unixy or not
>> haskelly enough to be appropriate for this mailing list?
>>
>> Thanks.
>>
>> --BEGIN PROGRAM--
>> module Main () where
>>
>> import Control.Monad
>> import System.IO
>> import System.Posix.Files
>>
>> pipeString = "/tmp/dld.fifo"
>>
>> main :: IO ()
>> main = do
>>        createNamedPipe pipeString $ unionFileModes ownerReadMode
>> ownerWriteMode
>>        pipe <- openFile pipeString ReadMode
>>        forever (hGetLine pipe >>= putStrLn)
>>
>>
>> --
>> mac
>> _______________________________________________
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>> http://www.haskell.org/mailman/listinfo/beginners
>>
>
>
>
> --
> =====================
> Patrick LeBoutillier
> Rosemère, Québec, Canada
>


-- 
mac