Thread safety of gr_wavfile_sink::close()

GNU Radio
1

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.

2

On Fri, Apr 30, 2010 at 07:42:32PM -0400, Don W. wrote:

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.

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.

Eric

3

----- Original Message -----
From: “Eric B.” [email protected]
To: “Don W.” [email protected]
Cc: “gnuradio mailing list” [email protected]
Sent: Friday, April 30, 2010 8:25 PM
Subject: Re: [Discuss-gnuradio] thread safety of
gr_wavfile_sink::close()

The reason I am interested is because I would like to do something
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.

4

On Fri, Apr 30, 2010 at 08:48:48PM -0400, Don W. wrote:

gr_wavfile_sink::close(). The description says it is thread safe
up.
So, it is ok to use the mutex across the work function?
Yes, as long as nobody who’s holding it ever blocks.

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.

Thanks!
Eric