Re: Request for help debugging screen problem

[Corinna Vinschen <corinna-cygwin at cygwin dot com>]

On Feb  5 10:42, Shaddy Baddah wrote:
> Hi,
> 
> I'm trying to debug a problem with screen, rather than publish a bug
> report. I can do that as well if someone requests it, no problem.
> 
> The issue I'm facing is with a read on the Windows named pipe
> associated with a tty device. I note that in this bit of code:
> 
> http://cygwin.com/cgi-bin/cvsweb.cgi/src/winsup/cygserver/transport_pipes.cc?annotate=1.12&cvsroot=src
> 
> 223: ssize_t
> 224: transport_layer_pipes::read (void *const buf, const size_t len)
> 225: {
> 226:   // verbose: debug_printf ("reading from pipe %p", _hPipe);
> 227:
> 228:   assert (_hPipe);
> 229:   assert (_hPipe != INVALID_HANDLE_VALUE);
> 230:   assert (!_is_listening_endpoint);
> 231:
> 232:   DWORD count;
> 233:   if (!ReadFile (_hPipe, buf, len, &count, NULL))
> 234:     {
> 235:       debug_printf ("error reading from pipe (%lu)", GetLastError ());
> 236:       SET_ERRNO (EINVAL);      // FIXME?
> 237:       return -1;
> 238:     }
> 239:
> 240:   return count;
> 241: }
> 242:
> 
> before and after the ReadFile the error code can return a different
> value. ie. a call to the following function, returns different
> values:
> 
> ssize_t client_request::error_code() const;
> 
> I'm curious as to how this could be. Is there some callback function
> registered via the Windows API that ReadFile calls at various points
> in its execution? Or is another thread setting this value?
> 
> Any help would be greatly appreciated.

Can yopu expolain this in more detail, please?  What error codes
are returned, and how do you trigger the effect?


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat