Re: [PATCH] [2.5] Non-blocking write can block

[Davide Libenzi]

On Thu, 5 Jun 2003, Mike Fedyk wrote:

> On Wed, Jun 04, 2003 at 05:19:05PM -0700, Davide Libenzi wrote:
> > Besides the stupid name O_REALLYNONBLOCK, it really should be different
> > from both O_NONBLOCK and O_NDELAY. Currently in Linux they both map to the
> > same value, so you really need a new value to not break binary compatibility.
>
> Hmm, wouldn't that be source and binary compatability?  If an app used
> O_NDELAY and O_NONBLOCK interchangably, then a change to O_NDELAY would
> break source compatability too.

Oh, that's for sure.

> Also, what do other UNIX OSes do?  Do they have seperate semantics for
> O_NONBLOCK and O_NDELAY?  If so, then it would probably be better to change
> O_NDELAY to be similar and add another feature at the same time as reducing
> platform specific codeing in userspace.

If I remember it correctly, they differ from the return value that you get
from blocking-candidate functions (0 <-> -1).

- Davide