Re: [Xenomai-help] newby question, can/socket stuff

[Jan Kiszka <jan.kiszka@domain.hid>]

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roland Tollenaar wrote:
> Hi,
> 
> 
> You must all be getting very exasperated with me. :)

How did you guess this? ;)

> 
>> > I know too little of the basic socket programming. Not even sure my
>> > wording in the previous sentence is capturing the correct area of
>> > ignorance.
>>
>> There are plenty text books on BSD socket programming and the rational
>> behind it.
> These are the ones I need. But without the time to get hold of them I
> will have to search the net.

"man" is your friend (if installed on your linux distro). E.g.

# man recvmsg

Then there is the OpenGroups spec:

http://www.opengroup.org/onlinepubs/009695399/

But I thing before diving too deep into this, rather apply the
Chinaman's tactic.

> 
>> > ret = rt_dev_ioctl(can_fd, SIOCGIFINDEX, &ifr);
>> >
>> > and
>> > ret = rt_dev_ioctl(can_fd, SIOCSCANBAUDRATE, &ifr);
>> >
>> > But exactly what is happening is beyond me at the moment.
>>
>> SIOCGIFINDEX gets the interface index for a named device and
>> SIOCSCANBAUDRATE allows to set the baudrate. The RT-Socket-CAN utilities
> 
> My email must have been very bad. I realize roughly what SIOCGIFINDEX
> and  SIOCSCANBAUDRATE do. This is described very nicely in your
> documentation or rather the documentation that refers to you and which
> Gilles kindly also pointed out to me but which I already knew about.
> 
> No my problem is with the
> rt_dev_ioctl
> 
> part. I would like to have a better understanding of the part that
> these functions play.

Add 1 to 1: The CAN profile describes what IOCTLs are available for CAN
sockets. rt_dev_ioctl() (or ioctl() with the POSIX skin) is the way to
pass these IOCTLs down to the CAN stack.

I think this should be visible when making one step back, looking at the
whole picture of the documentation pieces and the examples, no?

> 
>> are now even hyperlinked with the API doc (still not 100% perfect yet)
>> e.g.:
>>
>> http://www.xenomai.org/documentation/trunk/html/api/rtcanconfig_8c-example.html
>>
> 
> And by tremendous chance this was also the code I was studying when I
> posted my email.
> 
> Sorry to be such a nuisance. I'll see if I can google for some info on
> rt_dev_ioctl.
> 
> Regards,
> 
> Roland
> 

Jan


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