sendmsg/recvmsg file descriptor passing

sendmsg/recvmsg file descriptor passing

[David Rosenbloom]

I am unable to get sendmsg and recvmsg to successfully pass open file
descriptors between processes. I am using the Stevens APUE sample as a template,
the 4.3BSD version, since that matches the msghdr struct in cygwin/socket.h. I
notice a bunch of postings in the archive indicating (a) that file descriptor
passing was not supported at one time, and (b) that it may have been
subsequently added - I can't tell from the threads.

What is the current status of this? If implemented, does it have any caveats or
conditions which differ from the BSD implementation? If not implemented for the
passing of open file descriptors, is there an alternative approach (for two
cygwin processes)?

tia,
 - davidr



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Re: sendmsg/recvmsg file descriptor passing

[Brian Ford]

On Thu, 15 Jan 2004, David Rosenbloom wrote:

> I am unable to get sendmsg and recvmsg to successfully pass open file
> descriptors between processes. I am using the Stevens APUE sample as a template,
> the 4.3BSD version, since that matches the msghdr struct in cygwin/socket.h. I
> notice a bunch of postings in the archive indicating (a) that file descriptor
> passing was not supported at one time, and (b) that it may have been
> subsequently added - I can't tell from the threads.
>
I haven't seen any that imply it has been added.

http://sources.redhat.com/ml/cygwin/2004-01/msg00060.html

seems pretty clear to me.

-- 
Brian Ford
Senior Realtime Software Engineer
VITAL - Visual Simulation Systems
FlightSafety International
Phone: 314-551-8460
Fax:   314-551-8444

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Re: sendmsg/recvmsg file descriptor passing

[David Rosenbloom]

Thanks for the clarification - I missed that post, and was distracted by this
earlier one, which induced optimism:
http://sources.redhat.com/ml/cygwin/2002-06/msg00657.html

So apparently that's that for file descriptor passing. Plz advise if there's
another method that works in cygwin.

- davidr



On Thu, 15 Jan 2004, Brian Ford wrote:

> On Thu, 15 Jan 2004, David Rosenbloom wrote:
>
> > I am unable to get sendmsg and recvmsg to successfully pass open file
> > descriptors between processes. I am using the Stevens APUE sample as a template,
> > the 4.3BSD version, since that matches the msghdr struct in cygwin/socket.h. I
> > notice a bunch of postings in the archive indicating (a) that file descriptor
> > passing was not supported at one time, and (b) that it may have been
> > subsequently added - I can't tell from the threads.
> >
> I haven't seen any that imply it has been added.
>
> http://sources.redhat.com/ml/cygwin/2004-01/msg00060.html
>
> seems pretty clear to me.
>
> --
> Brian Ford
> Senior Realtime Software Engineer
> VITAL - Visual Simulation Systems
> FlightSafety International
> Phone: 314-551-8460
> Fax:   314-551-8444
>

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