Re: Sound Programming and Signals

[chuckw@ieee.org]

On Thu, Jun 13, 2002 at 10:48:00PM +0100, Glynn Clements wrote:
> 
> Chuck Winters wrote:
> 
> > I am trying to write a program which get a SIGIO signal from a
> > sound device, and then selects on the fd to decide if the device
> > can accept write, read, exception data.  The problem is that
> > it doesn't seem like the device every raises a SIGIO signal.  If
> > I do a kill -SIGIO <test_pid>, my handler runs.  Anyone have any ideas?
> 
> 1. Did you set the O_ASYNC flag on the descriptor, either in the call
> to open(), or with a subsequent call to fcntl(fd, F_SETFL, O_ASYNC)?
I used fcntl(fd, F_SETFL, f_flags|F_ASYNC)
after I used the F_SETOWN fcntl.  
> 
> 2. Did you set the target process ID with fcntl(fd, F_SETOWN, pid)?
> 
> If you have done both of these, but you still don't receive SIGIO,
> then I would suspect that it's a limitation of the sound card driver.
That really sucks then.  I thought all the drivers would support that.

Thanks
Chuck