c/unix q

[Erez D]

thanks,

so i guess if i use unidirectional connection, and the reader does not
expect to get an EOF()
thank i'm safe.

thanks,
erez.


On Tue, Jun 4, 2013 at 3:23 PM, Amos Shapira <amos.shapira at gmail.com> wrote:

> On 4 June 2013 21:43, ronys <ronys at gmx.net> wrote:
>
>> Nothing. You're just wasting resources (file descriptors) and making your
>> code a bit harder to understand and maintain.
>>
>> Note that for pipe(), you can use both fds at both ends of the pipe, but
>> it's very easy to get into a race condition.Better to open a pair of pipes,
>> one for each direction (of course, you now need to worry about
>> deadlocks...).
>>
>
> And about this one (race conditions) - any two processes using pipes
> (which have limited buffer size) to talk to each other bi-directionally run
> the risk of a deadlock if not coded carefully since they can easily reach a
> point where both of them block on write(2) which will only unblock when the
> other side read(2)'s and frees up space in the buffer (but the other side
> is blocked on a write - that's why it's called a "deadlock"). Typical ways
> to avoid that are to create threads to watch the fd's or use none-blocking
> IO.
>
>
>>
>> Rony
>>
>>
>> On Tue, Jun 4, 2013 at 2:24 PM, Erez D <erez0001 at gmail.com> wrote:
>>
>>> hello
>>>
>>> using the usual pipe()+fork()+dup()+close() to fork a child process and
>>> pipe data from and to it,
>>>
>>> I  know both the child and parent must close the unused fds.
>>>
>>> why ?
>>> what if i don't close the unsed fds ?
>>>
>>>
>>> thanks,
>>> erez.
>>>
>>>
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>>>
>>>
>>
>>
>> --
>> Ubi dubium, ibi libertas (where there is doubt, there is freedom)
>>
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>
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