bug#9860: 24.0.90; no auto-fill in c-mode when line begins with #

[Alan Mackenzie]

Hello, Peter.

Thank you for taking the trouble to submit this bug report all these
years ago, and sorry it's taken so long to attend to it.

The problem was a simple coding error, checking for a macro before
checking whether or not we were in a comment.  Your line of "#bla bla
...." was thus handled as a macro, and by the default setting of
`c-ignore-auto-file' didn't get filled.

I have now fixed this in the Emacs master branch, which will be getting
released as Emacs-30.1 maybe in a year's time.  I'm closing the bug with
this post.

If you would like to try out the fix yourself, here is the patch, which
needs to be applied in directory lisp/progmodes in the Emacs source
tree.



diff -r 0e6ebd732cbe cc-cmds.el
--- a/cc-cmds.el        Sat Oct 14 18:56:50 2023 +0000
+++ b/cc-cmds.el        Sun Oct 15 10:41:42 2023 +0000
@@ -4887,7 +4887,8 @@
           (setq c-lit-limits (c-literal-limits nil nil t)))
         (unless c-lit-type
           (setq c-lit-type (c-literal-type c-lit-limits)))
-        (if (memq (cond ((c-query-and-set-macro-start) 'cpp)
+        (if (memq (cond ((memq c-lit-type '(c c++ string)) c-lit-type)
+                        ((c-query-and-set-macro-start) 'cpp)
                         ((null c-lit-type) 'code)
                         (t c-lit-type))
                   c-ignore-auto-fill)



On Mon, Oct 24, 2011 at 21:33:08 +0200, Peter Münster wrote:
> Hello,

> With latest bzr-emacs:
> - emacs -Q
> - open "foo.c"
> - turn on auto-fill (M-x auto-fill-mode)
> - write the following comment:

> --8<---------------cut here---------------start------------->8---
> /*
> #bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla
> --8<---------------cut here---------------end--------------->8---

> - result: auto-fill does not work here

> In GNU Emacs 24.0.90.2 (x86_64-suse-linux-gnu, GTK+ Version 2.22.1)
>  of 2011-10-23 on micropit
> Windowing system distributor `The X.Org Foundation', version 11.0.10903000
> configured using `configure  '--without-toolkit-scroll-bars''

> Important settings:
>   value of $LC_ALL: nil
>   value of $LC_COLLATE: nil
>   value of $LC_CTYPE: en_GB.utf8
>   value of $LC_MESSAGES: nil
>   value of $LC_MONETARY: nil
>   value of $LC_NUMERIC: nil
>   value of $LC_TIME: nil
>   value of $LANG: nil
>   value of $XMODIFIERS: @im=local
>   locale-coding-system: utf-8-unix
>   default enable-multibyte-characters: t

> -- 
>            Peter

-- 
Alan Mackenzie (Nuremberg, Germany).