Hi,
I tested it, it works. I used a simple C program :
#include <sys/ioctl.h>
#include <stdio.h>
#include <fcntl.h>
int main(int argc, char **argv)
{
    int fd = open(argv[1], O_RDWR);
    struct winsize sz;
    sz.ws_row = atoi(argv[2]);
    sz.ws_col = atoi(argv[3]);
    ioctl(fd, TIOCSWINSZ, &sz);
    return 0;
}

Then in lisp, I added a hook to window-configuration-change-hook to call
this program with (process-tty-name), (window-width) and (window-height).
Interestingly, it worked in bash without needing a SIGWINCH, even when
deactivating the bash option in shopt that tells it to check for window size
changes.
I searched in the lisp manual, I didn't find any way to do what I did in C
in lisp. Is it possible ? Else a wrapper either to ioctl or directly
something like (change-size ttyname row col) (I don't know which one is
better) would need to be implemented in the C source code.
The resulting code in shell.el would like like :
(add-hook 'window-configuration-change-hook
      (lambda ()
        (if (eq major-mode 'shell-mode) (change-size))))

(defun change-size ()
  (ioctl (process-tty-name) (window-height) (window-size))
  (signal-process (get-buffer-process (current-buffer)) 'SIGWINCH))

There's many issues going on here I don't have any clue on how to solve, but
should be easy for an emacs developper : namespace cluttering, error
treatment (when a shell is stopped for example), performance, portability,
addition of the C source code ... could anyone tackle these in order to
solve the bug ?

Antoine
2008/5/25 Jan Djärv <jan.h.d@swipnet.se>:

>
>
> Stefan Monnier skrev:
>
>  Problem is: sending "export COLUMNS=%d" won't do the right thing if the
>> process running currently isn't some bourne derivative.  E.g. if it's
>> `csh' or some completely different process.
>>
>
> I think the right thing to do is to set the new size on the pty with ioctl
> TIOCSWINSZ and then send SIGWINCH to the inferior process.  AFAIK, shells
> react on that to set COLUMNS and LINES.  The signal is discarded by default
> so it does no harm if not caught.
>
>        Jan D.
>