Marc Lehmann wrote:
On Fri, Dec 14, 2007 at 12:56:00PM -0800, Scott Lamb <[EMAIL PROTECTED]> wrote:
Tests and results here:
http://www.slamb.org/svn/repos/trunk/projects/socket_tests/index.html
"The UNIX socket API has been standardized for a decade. But the standards
are vague on a lot of critical behavior."
In defendence of the standards (in this case the single unix spec.),
the blocking behaviour is _mandated_ by the SUS, and not following this
behaviour is a bug if the platform claims to follow unix behaviour. Of
course, OS X is quite far from any unix behaviour, so the portability
problem remains.
The problems are, however, far fewer in number if one only tests unix
platforms, which also have problematic behaviours but overall perform much
better than the unix emulation in os x.
I'm not going to get into stupid hairsplitting about what "unix
emulation" vs "unix platforms" means, but OS X's networking code was
largely inherited from FreeBSD. I would expect older FreeBSD systems to
have the same behavior.
However, that page has a lot of problems, for example it requires
non-standard behaviour and declares standard behaviour as "failure", an
example would be:
read(0) while connecting
EWOULDBLOCK failure (linux)
0 failure (os x)
EWOULDBLOCK is not a standard error code, the standard only documents EAGAIN
(which is what linux actually returns). The test expects EINPROGRESS, but
that is not allowed by the unix standard, so a platform actually getting a
green status there would be _broken_.
EWOULDBLOCK is how the Python library reported the error. On Linux,
EWOULDBLOCK and EAGAIN are synonymous.
Also, returning 0 is also allowed in this case, so the os x test is also
errornously marked as failing, when, in fact, it is fully standards
compliant.
So while the raw results of that page are very interesting, it would be
more useful if the interpretation as failure or not would not _require_
behaviour that is wrong by de-facto and actual standards.
I chose "failure" vs. "success" criteria rather arbitrarily - especially
in the cases where I couldn't find a clear answer in the standard, they
were basically just "was it the same as the first platform I tried
that test on". I should probably remove the color coding.
If you take a more thorough look at the page, you'll see a note to that
effect.
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