Re: [ECOS] ecos + lwip

[Simon Kallweit <simon dot kallweit at intefo dot ch>]

Mandeep Sandhu wrote:
> > Threads that use lwip APIs (netcomm and sockets) *must* be created with
> >  sys_new_thread(). Otherwise lwip's timeout mechanism will not work as
> > expected.
>
> Thanks for this info Simon.
>
> I'm stuck at how to pass an app supplied arg to my threads start function that's
> created using sys_thread_new().
>
> I want to pass an arg to my threads start function. I think the 2nd arg to
> sys_thread_new() seems to be user supplied arg, but from the usage I've seen
> that apps usually pass the thread's name to it in the 2nd arg.
>
> Internally, sys_thread_new uses this 2nd arg for both the name as well as the
> arg to the start function while calling cyg_thread_create(). So is there no way
> I can pass an arg to it (apart from the name)?

The implementation seems broken. I see three workarounds here:

1. Change the implementation to *not* use the user arg as the threads 
name, but provide a dummy name to cyg_create_thread() instead.
2. Define a struct with the first field being a dummy name, followed by 
any other fields you need and hand a pointer to this struct to 
sys_thread_new().
3. Use my new lwip port, which hopefully will soon be merged with eCos 
CVS. In the new release, sys_thread_new() takes both a thread name and a 
user argument, and uses them appropriately. Here is a preview release of 
lwip 1.3.1 for eCos. Just copy all the files in the archive over the 
eCos repository.

http://download.westlicht.ch/lwip-20090827.tar.gz

Simon

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