Re: [Xenomai-help] warnings and tangled threads.

[Wolfgang Grandegger <wg@domain.hid>]

roland Tollenaar wrote:
> HI
> 
>> That seems to be due to non-default -Wmissing-field-initializers, right?
>> Will have a look if we can quiet gcc.
> Possible.  I have received your patch. Will apply it (have to figure
> out how first) later and give feedback.
> 
> 
> 
>> > If rtcanrecv is not running then my application has no problems. I can
>> > see that it is writing by reading out /proc/rtcan/rtcan0/info looking
>> > at TxCount.
>> >
>> > I call can_write() directly after rt_task_wait_period so i did not
>> > think it necessary to use rt_task_shadow or such like in it.
>>
>> rt_task_shadow() is required if you call blocking services like
>> rt_task_wait_period from a task AND you didn't create it via some other
>> native service (rt_task_spawn or rt_task_create/start).
> Well then my code should be correct.
> 
> 
>> If the problem persists even with clean rt_task setup (rt_task_shadow
>> etc.), I guess it's best you post your code.
> Without changing my code I cannot repeat the behavior myself. Very
> strange. I have tried just about everything but after starting up the
> PC this morning there is no way I can repeat the behaviour I describe
> above.
> 
> So the can_write seems to be working for now. If it happens again I
> will post the code.
> 
> 
> I have more of a problem with reading. I am doing something wrong. The
> program does not return from the call rt_dev_recvfrom. Below is the
> simple read function I am presuming that whatever I am doing wrong
> will be blatantly obvious to all except me:)

At least it is not as in rtcanrecv.c ;-)

> void can_read(const char * device, can_frame_t * frame){
> 
>     int  ret;
>        struct ifreq ifr;
>     struct sockaddr_can addr;
>        socklen_t addrlen = sizeof(addr);
>     struct sockaddr_can recv_addr;
> 
>     strncpy(ifr.ifr_name, device, IFNAMSIZ);
>     ret = rt_dev_ioctl(can_fd, SIOCGIFINDEX, &ifr);
>     if (ret < 0) {
>         fprintf(stderr, "rt_dev_ioctl get index: %s\n", strerror(-ret));
>         return;
>     }
> 
>     recv_addr.can_family = AF_CAN;
>        recv_addr.can_ifindex = ifr.ifr_ifindex;
>        ret = rt_dev_bind(can_fd, (struct sockaddr *)&recv_addr,
> sizeof(struct sockaddr_can));
> 
>     if (ret < 0) {
>         fprintf(stderr, "rt_dev_bind: %s\n", strerror(-ret));
>         return;
>     }

The above code should go to the initialization routine after calling 
rt_dev_socket(). Ohterwise you query and bind the device for every read.

> printf("going in");
>     ret = rt_dev_recvfrom(can_fd, (void *)frame, sizeof(can_frame_t), 0,
> (struct sockaddr *)&addr, &addrlen);
> printf("coming out");

You should check the return code of rt_dev_recvfrom(). And  as you are 
not interested in the destination address, rt_dev_recv() should already 
work.

Nevertheless, the above code should work.

Wolfgang.