[Ace-users] [ace-users] ACE non-blocking SSL SOCK_Acceptor and FD_SETSIZE.. bug? (both 5.5 and 5.6.1)

Douglas C. Schmidt schmidt at dre.vanderbilt.edu
Mon Jan 7 19:17:20 CST 2008

Hi Kyle,

To ensure that we have proper version/platform/compiler information,
please make sure you fill out the appropriate problem report form
(PRF), which is in


or in


in older versions of ACE+TAO.  Make sure to include this information
when asking any questions about ACE+TAO since otherwise we have to
"guess" what version/platform/compiler/options you've using, which is
very error-prone and slows down our responsiveness.  If you don't use
the PRF, therefore, it is less likely that someone from the core
ACE+TAO developer team will be able to answer your question.
Naturally, we encourage and appreciate other members of the ACE+TAO
user community who can respond to questions that they have the answers

> I've been load testing a server application that uses epoll and non-
> blocking ACE SSL SOCK_Acceptor.  All seems well until the socket
> handles go to 1024 and roll over to negative, at which point things
> get messy. In many cases, the internals of the Countdown Timer seem
> to be corrupted at this point, specifically the pointer to it's
> max_time_value.  Best I can tell, this seems to be a result of the
> Handle_Set performing some FD_XXX operations on negative handles in
> the ssl accept routine. It appears to be a known issue that using
> select-based operations on handles greater than the FD_SETSIZE won't
> work out, but I would expect it to return an error, not corrupt
> nearby memory. Is this one of those "Don't do that" things, or
> should I file a bug report form?

It depends on what parts of ACE you're using.  If you're using the
higher-level ACE frameworks (e.g., the Reactor and Acceptor/Connector)
then it should handle this sort of thing for you.  If you're using the
lower-level stuff then it's probably a "don't do that" thing.


Dr. Douglas C. Schmidt                       Professor and Associate Chair
Electrical Engineering and Computer Science  TEL: (615) 343-8197
Vanderbilt University                        WEB: www.dre.vanderbilt.edu/~schmidt
Nashville, TN 37203                          NET: d.schmidt at vanderbilt.edu

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