🚀 go-pugleaf

Two people have recently had problems with "print-buffer", not
producing any output, but claiming that "Spooling...done".  The
problem was due to a stray file called "lpr" in their current
directory. (Due to a ">" instead of "|" in a piped command.)
"print-buffer" calls "call-process-region", which uses the "exec-path"
as a search path, and starts in the current directory.  Emacs does not
check the execute permissions of the file, and blindly tries to
execute the file.  This fails, with a message like:-

Couldn't exec the program /home/platinum1/gray/work/lpr

but the message is not displayed.

I have modified print-region-1 to check on errors, by getting
call-process region to reporting them in a buffer called " *Spool
Messages*", and using the length of the buffer as an indication of the
success.

The new code is (started from lpr.el for emacs 18.55):-

(defun print-region-1 (start end switches)
  ;;
  ;;  Tue Mar 19 10:36:49 1991; D.Gray Stephens (gray@scr.slb.com)
  ;;  Modified function to report error message.
  (if
      (let ((name (concat (buffer-name) " Emacs buffer"))
	    (width tab-width))
	(save-excursion
	  (message "Spooling...")
	  (save-excursion
	    (set-buffer (get-buffer-create " *Spool Messages*"))
	    (kill-region (point-min) (point-max))
	    )
	  
	  (if (/= tab-width 8)
	      (let ((oldbuf (current-buffer)))
		(set-buffer (get-buffer-create " *spool temp*"))
		(widen) (erase-buffer)
		(insert-buffer-substring oldbuf start end)
		(setq tab-width width)
		(untabify (point-min) (point-max))
		(setq start (point-min) end (point-max))))
	  (apply 'call-process-region
		 (nconc (list start end lpr-command
			      nil " *Spool Messages*" nil)
			(nconc (and (eq system-type 'berkeley-unix)
				    (list "-J" name "-T" name))
			       switches)))
	  (set-buffer (get-buffer " *Spool Messages*"))
	  (= (count-lines (point-min) (point-max)) 0)
	  ))
      (message "Spooling...done")
    (switch-to-buffer-other-window " *Spool Messages*")
    (message "Spooling...failed")
    )
  )


Can the next version of emacs be modified to include a similar check?

As a second, and minor, point, I prefer to to include my user name on
the title for print-buffer, as several users access the same printer.
I modify the "name" to be

      (let ((name (concat (upcase (getenv "USER")) "\'s " (buffer-name) 
			  " Emacs buffer"))

Maybe a print-hook could be provided to enable user's to customise the
title?

I trust these comments are helpful, and look forward to the next
version of emacs.

Douglas Gray Stephens