char-displayable-p returns t for undisplayable characters

[Jonathan Yavner]

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Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

Using "emacs -nw" inside xterm under RedHat 8.0

For utf8 locale, the character '…' (ellipsis) displays as a blank.  A call to
(char-displayable-p ?…) returns t, but this character is not displayable.  The
character 'é' (e-acute) displays properly.

For iso88591 and iso885915 locales, 'é' (e-acute) displays as a blank while
'…' (ellipsis) displays reasonably as a question mark.  In this case,
char-displayable-p returns t for the e-acute that displays a blank, but
returns nil for the ellipsis that displays as a question mark.

Note: xterm in locale iso88591 *can* display an e-acute, but not when running
Emacs.  Why?

Under X11, the e-acute and ellipsis characters both display properly in Emacs, 
while '√' (square root) displays as a white rectangle.  char-displayable-p 
returns non-nil for the square-root character, and other programs on my 
computer (such as kmail) can display that character.

I had planned to use char-displayable-p to decide whether an ellipsis can be
displayed for a truncated field, with fallback to a dollar sign if not.  Is
there any way to tell whether a character is actually displayable, rather than
whether the current locale has a slot for it?


In GNU Emacs 21.3.50.5 (i686-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2004-01-24 on Daddy
Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.utf8
  locale-coding-system: utf-8
  default-enable-multibyte-characters: t

Recent input:
n a l / m u l e - u t i l RET C-x ESC ESC C-b C-b C-b 
C-f . e l RET C-x ESC ESC ESC b ESC b ESC b C-u C-b 
C-u C-b C-d RET ESC : ( c h a r - d i s p l a y a b 
l e - p SPC ( d e c o d e - c h a r SPC ' u c s SPC 
8 2 3 0 ) ) RET ESC x r e p o r t - e m TAB RET

Recent messages:
Loading server...done
For information about the GNU Project and its goals, type C-h C-p.
Loading iso-transl...done
nil
Quit
Loading /usr/local/emacs/lisp/international/mule-util.el (source)...done
t
Loading emacsbug...done