🚀 go-pugleaf

In GNU Emacs 19.27.3 (rs6000-ibm-aix3.2.5, X toolkit) of Fri Sep 23 1994
on mended_drum

This one's been bothering me for ages and I've finally tracked it
down...

Start up emacs -q -no-site-file (just to make sure it's clean) and
edit the file c.c which contains the following code:-

--  c.c  -------------------------------------------------------------

int main (int argc, char *argv[])
{
  printf ("Hello world!\n");

  /*******/

  printf ("Hello world!\n");
}

----------------------------------------------------------------------

Now do M-x font-lock-mode.  The string after the first printf gets
fontified as expected (in the underline face) as does the comment (in
italics) but the second string *doesn't* get fontified.

This seems to be because `comment-start-skip' is swallowing the start
of the comment end.  You can prove this in two ways:-

(1) change the comment to "/****** */", save the file, revisit it by
    doing C-x C-v RET, then do font-lock-mode.  Everything gets
    fontified as expected.

(2) (with the original "/*******/" comment) turn off font-lock-mode
    with C-u - M-x font-lock-mode RET, change comment-start-skip by
    doing M-x set-variable RET comment-start-skip RET "/\\*" RET, then
    turn on font-lock-mode.  Again, everything gets fontified
    correctly.

I haven't had a chance to look into font-lock.el to see what's going
wrong, but it shouldn't be too difficult to spot.

--
Kevin