About `char' in momentary-string-display

[Xue Fuqiao <xfq.free@gmail.com>]

Hi,

In (info "(elisp) Temporary Displays"):

 -- Function: momentary-string-display string position &optional char
          message
[...]
     Thus, typing CHAR will simply remove the string from the display,
     while typing (say) `C-f' will remove the string from the display
     and later (presumably) move point forward.  The argument CHAR is a
     space by default.

I tried evaluating ‘(momentary-string-display "foo" 1)’ in the *scratch*
buffer and typed ‘C-f’, but the point didn't move forward.  Instead, a
‘[6]’ is echoed in the *Messages* buffer.  I don't know what the ‘[6]’
stands for, but the codepoint for ^F is #x6 (ACK).  So I think there may
be a link between them.

But anyway, why didn't the point move forward (the point wasn't at eob)?
Can anyone point me in the right direction?

(I searched the archives, but didn't get anything that looked promising.)

-- 
Best regards, Xue Fuqiao.
http://www.gnu.org/software/emacs/