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https://issues.apache.org/jira/browse/QPID-1982?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12730476#action_12730476
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Ted Ross commented on QPID-1982:
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The interfaces in qpid/cpp/src/qmf are intended to be wrapped with bindings for
various languages (Ruby, Python, C++, etc.). The language-specific wrapper (or
driver) is responsible for determining what the threading model is for its API.
The notifyFd can be abstracted but is has to be usable in a select/poll
construct in any language.
What is needed is a language-agnostic way of waking up a thread or process when
it has work to do. It would be straight forward to replace "int" with a
defined type and to replace "::write()" with a macro. I'm not sure, however,
how the driver-side can be abstracted. It is not sufficient to have a blocking
call that returns when there is work to do because the application may need to
simultaneously be watching other sources of events (e.g. with select or poll).
> QMF ResilientConnection notifyFd feature portability
> ----------------------------------------------------
>
> Key: QPID-1982
> URL: https://issues.apache.org/jira/browse/QPID-1982
> Project: Qpid
> Issue Type: Improvement
> Components: Qpid Managment Framework
> Affects Versions: 0.5
> Environment: Windows
> Reporter: Steve Huston
>
> The QMF's C++ qmfcommon ResilientConnection class has a setNotifyFd (int fd)
> method. The docs say this can receive a file descriptor that is written on
> when certain events take place, supposedly so the other end of the channel
> can listen, select, etc. and be notified of some event.
> This construct isn't portable, both because of the datatype of the fd (int is
> not necessarily a legit handle type everywhere) and because the code assumes
> a write() will work. The code can be abstracted out to get rid of the write()
> easily enough, but what is the usage for this facility? There are no calls to
> setNotifyFd() that I can find outside of the library containing the
> implementation. So I can't tell if this is something that can be replaced by
> qpid::sys::PollableCondition or not.
> What is the use case for this, and how can we make this portable? Different
> IPC type? Callback to some private hook?
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