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Re: Documentation of eventfd_write and eventfd_read?
- From: Hei Chan <structurechart at yahoo dot com>
- To: Carlos O'Donell <carlos at redhat dot com>
- Cc: "libc-help at sourceware dot org" <libc-help at sourceware dot org>
- Date: Tue, 4 Feb 2014 02:27:17 -0800 (PST)
- Subject: Re: Documentation of eventfd_write and eventfd_read?
- Authentication-results: sourceware.org; auth=none
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- Reply-to: Hei Chan <structurechart at yahoo dot com>
Maybe my wording somehow confused you.
I didn't use epoll_wait() to wait on the file descriptor I passed to eventfd_write.
I have filed a bug here: https://sourceware.org/bugzilla/show_bug.cgi?id=16524
If anyone is interested, you can check the feedback later.
Thanks all!
On Tuesday, February 4, 2014 12:37 AM, Carlos O'Donell <carlos@redhat.com> wrote:
On 02/01/2014 12:54 AM, Hei Chan wrote:
> Sounds like a bug that epoll_wait() doesn't return when
> eventfd_write() is called with zero as the 2nd argument?
It's a bug somewhere.
An eventfd_t value of 0 does not impact the fact that the
underlying write uses &value and writes the size of the
descriptor into the buffer.
That should be sufficient to wake any waiter that is
waiting on data.
The better question is:
Is it valid to use an eventfd fd in epoll_wait which
expects an epoll fd?
I don't know how well tested this is, but one would expect
it to work on any fd.
Cheers,
Carlos.