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

[Chong Yidong]

Kazuhiro Ito <kzhr@d1.dion.ne.jp> writes:

>> 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.
>
> I noticed this problem is not Windows specific.  I confirmed that it
> is reproducible in Emacs 23.3.1 (build by pkgsrc) on NetBSD/amd64 via
> SSH from remote host.  But it doesn't occur on openSUSE 11.3.

Could you run Emacs under a debugger, trigger the crash, and provide a
backtrace?  (You will need to have compiled Emacs with debugging
symbols.)