Igor Pechtchanski a écrit :
  > Cygwin uses something called "ptys", which are pseudo-terminals
> implemented with pipes.  Some Windows applications don't understand those,
> so think they're running without a console, and allocate their own.  There
> was some work on fixing this -- see the Cygwin mailing list archives for
> details, but I don't think there's a definitive resolution.

Thanks. I will have a look.

> You most likely run Cygwin's emacs, which creates ptys.  You could try
> using non-Cygwin xemacs (I don't know if it speaks X -- I don't use
> emacs).

But what seems strange to me is that my own version of the toplevel 
works fine...

> That said, why not use the Cygwin version of O'Caml that does understand
> ptys?

I use Ocaml at work (this explains my use of windows - but not all the 
time...). Usually, except little standalone utilities, I generate DLLs, 
which are called by other languages (Java, Labview, C++). I do not know 
how to do those DLLs with cygwin tools. And I would have to use mingw 
version because of licence problems.

> Igor Pechtchanski, the volunteer O'Caml maintainer for Cygwin

Salutations

Matthieu