[Twisted-Python] Opening a fifo
p.mayers at imperial.ac.uk
Fri Nov 14 06:00:33 EST 2008
Paul Thomas wrote:
> On 14 Nov 2008, at 09:47, Phil Mayers wrote:
>> Paul Thomas wrote:
>>> I've run into a small problem where my twisted application needs to
>>> open a fifo to talk to another process. On Linux at least, the open
>>> blocks until the other end of the fifo is opened and this is blocking
>>> my reactor.
>> Either of:
>> fd = os.open('thefifo', os.O_RDONLY | os.O_NONBLOCK)
>> fd = os.open('thefifo', os.O_RDWR)
>> ...will return immediately,
>> Try "man fifo" for a description of the vagaries.
> I've tried RDWR and I get errors in writing. I really need O_WRONLY, and
> that fails with O_NONBLOCK unless the other end is open. Maybe I'll
> chase down the RDWR problem again.
Really? It works for me in a repl:
[pjm3 at wildfire ~]$ mkfifo blah
[pjm3 at wildfire ~]$ python
>>> import os
>>> fd = os.open('blah', os.O_RDWR)
>>> os.write(fd, 'a')
What errors are you getting? Possibly Twisted is getting confused
because the fd is "readable" as well as "writeable".
Do you have sample code that's failing?
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