[Haskell-beginners] Named Pipes Et Cetera

[Patrick LeBoutillier]

Here's the uname -a output:

$ uname -a
Linux pc207 2.6.30.10-105.2.23.fc11.x86_64 #1 SMP Thu Feb 11 07:06:34
UTC 2010 x86_64 x86_64 x86_64 GNU/Linux

Patrick

On Tue, Nov 23, 2010 at 10:36 AM, Patrick LeBoutillier
<patrick.leboutillier at gmail.com> wrote:
> On Tue, Nov 23, 2010 at 9:13 AM, matthew coolbeth
> <mac01021 at engr.uconn.edu> wrote:
>> That's interesting.  This was using my source code?
>
> Yes, as is. I compiled it with "ghc --make pipe.hs".
>
> I'm running Fedora 10 x64 with:
> $ ghc --version
> The Glorious Glasgow Haskell Compilation System, version 6.10.1
>
> Patrick
>
>> 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
>>>> _______________________________________________
>>>> Beginners mailing list
>>>> Beginners at haskell.org
>>>> http://www.haskell.org/mailman/listinfo/beginners
>>>>
>>>
>>>
>>>
>>> --
>>> =====================
>>> Patrick LeBoutillier
>>> Rosemère, Québec, Canada
>>>
>>
>>
>> --
>> mac
>>
>
>
>
> --
> =====================
> Patrick LeBoutillier
> Rosemère, Québec, Canada
>



-- 
=====================
Patrick LeBoutillier
Rosemère, Québec, Canada