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

[Wolfgang Grandegger <wg@domain.hid>]

roland Tollenaar wrote:
> Hi,
> 
> I am looking through the rtcan code provided with the xenomai package
> and I realize one thing:
> 
> 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.

> I suspect very strongly that the rtcan functionality is designed to
> piggyback on whatever standard iocontrol is taking place in functions
> like
> 
> 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 
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

> Now I can obviously try to copy like a chinaman (no disrespect
> intended!) and not understand what I am doing but it is not really a
> mode of operation I relish.
> 
> I have briefly tried to locate the rt_dev_ioctl back to a xenomai
> header but have not managed to trace it yet.

> Is it defined in the standard linux ioctl headers? Where can I find
> some info on what arguments these functions are passed etc?

Hm, try:

$ cd <xenomai-root>
$ find . -name '*.[ch]' | xargs grep SIOCSCANBAUDRATE

> Much appreciated.

Wolfgang.