[irda-users] Re: How to get discovery & expiry notification?

[Jean T. <jt...@bo...>]

Lone Star wrote :
> 
>    I"m writing a user-space program, and want to get notified when
> device in range and out. After searching the archive,

	You read the archive ! I'm impressed !

> I wrote a small
> test program, doing select+read on  /dev/irnet:
> 
>         fd = open("/dev/irnet", O_RDONLY);
>         while(1) {
>            FD_ZERO(&rfds);
>            FD_SET(fd, &rfds);
>            retval = select(fd+1, &rfds, NULL, NULL, NULL);
>  
>            if(retval>0 && FD_ISSET(fd, &rfds)){
>                         len = read(fd, buf, 64);
>                         if(len>=0) 
>                                 printf("%d %s\n", len, buf);
>             }
>         }
> 
> But it doesn"t work as expected. GDB told me that the select returned
> immediately, with fd ready, but the following read never return.

	Yeah, I can see that. This bug only happens when you open the
file descriptor and the discovery log is empty. I will have to think
about how I could fix that, unfortunately this is not trivial.
	The reason I never saw it is because my /dev/irnet socket is
non-blocking. That's a nice workaround for you ;-)

> I put
> my Palm in range, then both irdadump and /proc/net/irda/discovery told
> me it has been discovered, but my test program didn"t read anything.

	IrNET filter discovery on the IrLAN bit, so your Palm won't
show up. One workaround would be to replace the S_LAN in the code...
	Too bad...

	Jean