RE: [ECOS] TCP/IP Stack packet regrouping

["Trenton D. Adams" <tadams at extremeeng dot com>]

  > 
  > On Mon, Jul 16, 2001 at 03:44:40PM -0600, Trenton D. Adams wrote:
  > 
  > >> No, that is not generally true.  For small blocks, it will
  > >> _usually_ be true.  For large blocks of data, you will have to
  > >> check the return value from write() in a loop.  The values of
  > >> "small" and "large" vary from platform to platform.
  > >
  > > Ok, who's actually correct here?  Who's the one that wrote the
  > > TCP/IP stack?  Are they listening?
  > 
  > After reindenting uipc_socket.c and looking at it some more, it
  > looks like the outer do/while loop in sosend() is waiting until
  > all data has been sent (for a blocking, stream socket).
  > 
  > The inner do/while loop fills up the so_snd buffer until it's
  > full. After the inner loop has filled up the send buffer, the
  > outer loop repeats the inner loop.  There ought to be someplace
  > in there where the task blocks waiting for more room in the
  > send buffer, but I cant find it.
  > 
  > But, the comment at the top of sosend() reads:
  > 
  >  * Returns nonzero on error, timeout or signal; callers
  >  * must check for short counts if EINTR/ERESTART are returned.
  >  * Data and control buffers are freed on return.
  > 
  > If you can guarantee that no signals are going to happen, then
  > you souldn't have to check for short counts. I don't like to
  > depend on that assumption.
  > 

I have now in fact tested eCos with a 40K string buffer.  I used strcat
() fill it with the same string + carriage returns over and over again.
I then used send () which in fact did send the entire text buffer.  So,
you are correct.

Now, about the signals thing!  Can eCos applications receive signals
like Linux does?  If not, then I don't care because my code has no need
to be portable to anything other than eCos.