Re: [Discuss-gnuradio] thread safety of gr_wavfile_sink::close()

[Don Ward]

----- Original Message ----- 
From: "Eric Blossom" <address@hidden>
To: "Don Ward" <address@hidden>
Cc: "gnuradio mailing list" <address@hidden>
Sent: Friday, April 30, 2010 8:25 PM
Subject: Re: [Discuss-gnuradio] thread safety of gr_wavfile_sink::close()


> On Fri, Apr 30, 2010 at 07:42:32PM -0400, Don Ward wrote:
> > I have a question about the thread safety of
> > gr_wavfile_sink::close().  The description says it is thread safe
> > and it uses d_mutex, but what is to stop the work() function from
> > writing the file at the same time that close() (via close_wav()) is
> > writing and closing the file?  gr_wavfile_sink::work() does not lock
> > d_mutex (except when d_updated is set).  Is there something going on
> > behind the scenes to prevent the threads from mangling the output
> > file, or is this a problem with the code?
> >
> > The reason I am interested is because I would like to do something
> > similar with gr_udp_sink, allowing one socket to be closed and a new
> > one to be created when one client finishes and another client starts
> > up.
> >
> > Thanks,
> >
> > -- Don W.
>
> It looks fairly hosed up.  One fundamental design/documentation
> problem is that the header file does not document which variables must
> be protected by the mutex.  Also, proper use of the mutex (including
> in work) would eliminate all of the code related to d_updated.

So, it is ok to use the mutex across the work function?

> While I'm at it, set_bits_per_sample quietly fails for any value not
> equal to 8 or 16.
>
> gr_udp_sink has similar problems.

Ok.  Let me work on gr_udp_sink, then you can tell me how close I came to 
getting it right.

-- Don W.