Re: Q: prevent Emacs from sending mail with no subject

[Kevin Rodgers <ihs_4664@yahoo.com>]

Eric Pement wrote:

> I would like to know how to prevent Emacs from sending email with no
> subject (or with a subject line that contains only whitespace). I've
> accidentally sent a couple of messages this way, and I think Emacs
> converted the subject line to "(unknown)" for me, but I'm not sure. At
> any rate, I want Emacs to not send the message if the subject line is
> empty, but to prompt me to enter the missing subject.
> 
> I've already checked the FAQ, the Customization menu, "Learning GNU
> Emacs" and searched the Google archives for this issue, but I can't
> seem to find the answer. Any help would be appreciated.

Emacs is not changing your Subject header (I just checked the lisp/mail/*.el
files distributed with Emacs 21.3).  It is probably your site's MTA -- are
you using sendmail.el or smtpmail.el, or something else?

In any case, you probably want to add the check for an empty Subject header
to mail-send-hook:

(defun mail-send-check-subject ()
   (save-excursion
     ;; see mail-position-on-field:
     (goto-char (point-min))
     (let ((case-fold-search t))
       (if (re-search-forward "^Subject:[ \t]*" (mail-header-end))
           ;; else signal an error
           (if (eolp)
               (insert (read-string "Subject: ")))))))

(add-hook 'mail-send-hook 'mail-send-check-subject)

-- 
Kevin Rodgers