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From: ron@mlfarm.UUCP (Ronald Florence)
Newsgroups: comp.emacs
Subject: using a subprocess for printing
Message-ID: <337@mlfarm.UUCP>
Date: 7 Oct 89 13:54:37 GMT
Organization: Maple Lawn Farm, Stonington, CT
Lines: 44

I would welcome suggestions on how to start a subprocess to run troff
on the contents of a GNU Emacs buffer.  Currently, I use the following
code

     (defun troff-buffer (&optional copies)
       "Typeset region contents after formatting with `troff -mm -rN2'.
     Optional prefix argument specifies number of copies."
       (interactive "P")
       (let ((buffer (get-buffer-create "*printer command output*")))
	 (save-excursion
	   (set-buffer buffer)
	   (erase-buffer))
	 (message "Spooling...")
	 (if (null copies) (setq copies "1"))
	 (call-process-region (point-min) (point-max) "emacstroff" 
			      nil buffer nil  
			      (concat "-n" copies))
	 (if (> (buffer-size) 0)
	     (progn
	       (set-buffer buffer)
	       (goto-char (point-min))
	       (end-of-line)
	       (message "%s" (buffer-substring 1 (point))))
	   (message "(Printer command failed)")))
       (kill-buffer "*printer command output*"))

The "emacstroff" is a shell script with printer and troff options

     :
     #! /bin/sh
     # emacstroff

     troff -t -mm -rN2 | lp -ot $1

It works, but I sit and twiddle my thumbs, staring at the
"Spooling..." message while troff formats.  Is there a way to use a
subprocess to do this?  We are running Emacs 18.50 with Xenix 2.3.2,
using the select() call.  There are plenty of free ptys for
subprocesses.

Thanks in advance for any suggestions.
-- 

Ronald Florence			{hsi,rayssd}!mlfarm!ron