bug#9318: 23.3.50; The first call of encode-coding-region() returns wrong result on on Windows

[Kazuhiro Ito <kzhr@d1.dion.ne.jp>]

When I start Emacs and evaluate the below code, unexpected result returns.

(let ((func (lambda ()
	      (with-temp-buffer
		(mapc 'insert '(166 25339))
		(encode-coding-region (point-min) (point-max) 'ctext-unix)
		(buffer-string)))))
  (cons (funcall func)
	(funcall func)))
-> ("¦拻^@^@^@^@^@^@^@^@^@^@" . "^[$(D\"C^[$(H*f^[(B") 

car of the result is not constant.  In the worst case, emacs
crashes.  It doesn't occur on Linux.  If I evaluate twice, car and cdr
of the last result are correct.  Using encode-coding-string instead of
encode-coding-region has no problem. 

(let ((func (lambda ()
	      (encode-coding-string
	       (mapconcat 'char-to-string '(166 25339) "")
	       'ctext-unix))))
  (cons (funcall func)
	(funcall func)))
-> ("^[$(D\"C^[$(H*f^[(B" . "^[$(D\"C^[$(H*f^[(B")

Before calling encode-coding-string also can avoid problem.

(let ((func (lambda ()
	      (with-temp-buffer
		(mapc 'insert '(166 25339))
		(encode-coding-region (point-min) (point-max) 'ctext-unix)
		(buffer-string)))))
  (encode-coding-string
   (mapconcat 'char-to-string '(166 25339) "") 'ctext-unix)
  (cons (funcall func)
	(funcall func)))
-> ("^[$(D\"C^[$(H*f^[(B" . "^[$(D\"C^[$(H*f^[(B")

-- 
Kazuhiro Ito