Missing the AF_BUS

Posted Jul 12, 2012 6:31 UTC (Thu) by michelp (guest, #44955)
In reply to: Missing the AF_BUS by michelp
Parent article: Missing the AF_BUS

I guess I should point out it's also going about it by implementing a protocol family similar to AF_BUS. Why can't we have d-bus and more? There are plenty of useful patterns out there and many available protocol family constants. If it's well tested and performant and cleanly coded, then why reject it? Is't that the purpose of having extensible protocol families? It's not like it's going to screw up any existing code.

Missing the AF_BUS

Posted Jul 12, 2012 6:57 UTC (Thu) by neilbrown (subscriber, #359) [Link] (1 responses)

Don't under-estimate the maintenance burden of adding more code.

It is true that we seem to add filesystems with gay abandon so maybe a similar case could be added for address families...

The reason that I would avoid adding multiple address families for IPC is that someone would want a mix of features from one and features from another (e.g. multicast and fd passing from AF_INET and AF_UNIX). So would we add yet another one that does both?

Missing the AF_BUS

Posted Jul 12, 2012 15:02 UTC (Thu) by michelp (guest, #44955) [Link]

> Don't under-estimate the maintenance burden of adding more code.

Can you give me an example of who is burdened by what exactly in this case?

> The reason that I would avoid adding multiple address families for IPC is
> that someone would want a mix of features from one and features from
> another (e.g. multicast and fd passing from AF_INET and AF_UNIX). So
> would we add yet another one that does both?

That seems like a speculative reason to reject existing and well established software patterns like d-bus, that are correctly leveraging a well established extension mechanism for adding new protocol families. Again, if it wasn't meant to be extended, then why have protocol families at all? Why was the 'sk is first member of the struct' pattern so well thought out from the beginning? It was done this way to provide ways for the mechanism to grow and evolve.