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Re: [1.7] fifo regression
- From: Eric Blake <ebb9 at byu dot net>
- To: cygwin at cygwin dot com
- Date: Mon, 06 Jul 2009 07:12:27 -0600
- Subject: Re: [1.7] fifo regression
- References: <4A51F60F.2030304@byu.net>
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According to Eric Blake on 7/6/2009 7:03 AM:
> But on cygwin 1.7, when you attempt to create multiple writers to a single
> fifo, the second writer creates an fd just fine but then fails on any
> attempt to write to that fd:
>
> $ mkfifo fifo
> $ (exec 5>fifo; sleep 25; echo one >&5)&
> [1] 4200
> $ (exec 5>fifo; sleep 15; echo two >&5)&
> [2] 204
It appears that part of the problem is that cygwin is violating POSIX - a
process that opens a fifo for writes must block until a corresponding
process opens the same fifo for reads, but cygwin is creating the fd
without blocking. A pstree at this point shows that the sleep processes
have already been spawned...
> $ exec 5<fifo
...even though on Linux, the sleeps cannot spawn until after this point.
- --
Don't work too hard, make some time for fun as well!
Eric Blake ebb9@byu.net
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