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Message-ID: <010c01c0b576$a93cdb00$0200a8c0@lifelesswks>
From: "Robert Collins" <robert DOT collins AT itdomain DOT com DOT au>
To: <cygwin-developers AT cygwin DOT com>
References: <001b01c0b397$2d1ca720$0200a8c0 AT lifelesswks> <1783665564 DOT 20010323155742 AT logos-m DOT ru> <000501c0b3e9$7fa3d890$0200a8c0 AT lifelesswks> <183264218826 DOT 20010325190658 AT logos-m DOT ru> <005b01c0b575$112ff2d0$0200a8c0 AT lifelesswks> <20010325165305 DOT A32188 AT redhat DOT com>
Subject: Re: setup will have to wait :[
Date: Mon, 26 Mar 2001 07:57:59 +1000
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----- Original Message -----
From: "Christopher Faylor" <cgf AT redhat DOT com>
To: "Egor Duda" <cygwin-developers AT cygwin DOT com>
Sent: Monday, March 26, 2001 7:53 AM
Subject: Re: setup will have to wait :[


> On Mon, Mar 26, 2001 at 07:46:35AM +1000, Robert Collins wrote:
> >----- Original Message -----
> >From: "Egor Duda" <deo AT logos-m DOT ru>
> >Subject: Re: setup will have to wait :[
> >
> >
> >> Hi!
> >>
> >> Saturday, 24 March, 2001 Robert Collins
robert DOT collins AT itdomain DOT com DOT au
> >wrote:
> >>
> >Right, so _how do we pass the fd_ to the child process? I'll look
into
> >spawn and fork. Worst case though: fifos are cygwin only. Best case I
> >find some way of tricking the OS into loading up the cygwin code and
> >writing "through it". Hmm I wonder if an IFS could do this (How much
> >work did I think this was going to be ?!).
>
> They're inherited automatically.  The fd table is copied
automatically.
> Non-cygwin processes inherit the handles but they won't know what to
do
> with them since they don't understand cygwin fds.

Thanks.

> >> RC> I know that cygwin already has named pipe support
> >>
> >> ? what do you mean by this? do you mean native calls such as
> >> CreateNamedPipe () etc. or something else?
> >
> >>From comments about sshd and cvs on 9x and the syncronisation
problems -
> >so I may be off base. I haven't checked the code. Implementing this
via
> >Named Pipes will be just as tricky as far as non-cygwin programs
though
> >won't it?.
>
> You can't use named pipes.  You can't create them on Windows 95.

Well I'm glad I wasn't planning on useing them anyway :]

> Cygwin doesn't implement named pipes.  Isn't a fifo == a named pipe
> anyway?

Yes. I'm looking into the behaviour in more detail defore I cut code,
but yes. My planned implementation is a shared memory region that lists
the named pipes open on the system (maintained automagically via any
open cygwin process), a couple of waitable objects (probably 1 semaphore
and 1 event) per open fifo, and finally a (pick a good buffer size)
shared memory region for doing the actual data transfer.

> cgf
>

Rob