Re: [Patch] Resizing shells in shell-mode

[Antoine Levitt]

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 <address@hidden>:

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.