Re: [libdc1394-devel] dc1394_capture_dequeue hangs on os x after unclean quit

[Ulrich v. Z. <uz...@li...>]

Aaron Stafford wrote:
> I am using libdc1394 (version 2) on os x to read images off of a 
> dragonfly camera from point grey. I wrote some code that uses 
> DC1394_CAPTURE_POLICY_WAIT with the dc1394_capture_dequeue. In general 
> everything works great, but...
> 
> If I control-c out of my application (i run it from a terminal), rather 
> than exiting it nicely, and then try and run my application again within 
> a few seconds everything will work for about a second and then 
> dc1394_capture_dequeue just hangs and never recovers.
> 
> If I put it in DC1394_CAPTURE_POLICY_POLL mode instead and run the code 
> again rather than the blocking that I experienced previously 
> dc1394_capture_dequeue ends up returning an error of -2 (the error 
> string for this is "null").
> 
> Is there a solution to this? I can't guarantee that my program will 
> always exit nicely.

I don't know what we're doing differently, but we use 
odc1394_capture_dequeue_dma(m_pCamera, DC1394_VIDEO1394_WAIT); on os x, 
and I just checked. The problem doesn't appear here. It might be that 
the *_dma functions don't have the issue. It might also be an issue with 
different versions of the library (2.0rc4 here), or something entirely 
different.

You can have a look at our code here to see what we're doing differently:

https://www.libavg.de/websvn/listing.php?repname=libavg&path=%2Ftrunk%2Flibavg%2Fsrc%2Fimaging%2F&rev=0&sc=0

Most of the camera stuff is in Camera.cpp.

Regards,

   Uli