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Date:	Thu, 19 Jul 2012 06:42:47 -0600
From:	Eric Blake <eblake AT redhat DOT com>
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Subject:	Re: Problem with <> redirection to named pipe
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On 07/19/2012 12:53 AM, Nikolay Shirokovskiy wrote:
> Hello.
>=20
> When I try:
>=20
>> mkfifo fifo
>> exec 5<>fifo

POSIX says this is non-portable.  You cannot expect it to work everywhere.

>=20
> I get "Device or resource busy" error message. On linux distro these
> lines work well.

As an extension to POSIX, but not as a standard.

>=20
> I made some browising through archives and encountered notices that
> FIFOs implementation
> in Cygwin is incomplete. Is this the cause or I miss something?

I don't know if cgf's recent work on fifos has achieved the same
extension as Linux of being able to open a fifo for read-write; but I
know that Autoconf specifically avoids using <> on fifos, and instead
uses a background subshell where the two forks of the shell coordinate
which shell opens for read and the other opens for write, precisely
because of cygwin.

--=20
Eric Blake   eblake AT redhat DOT com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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