Hello, Po.

Thanks for the high quality bug report.

On Tue, May 02, 2023 at 15:31:51 +0800, Po Lu via CC-Mode-help wrote:
> Package: cc-mode

> Insert:

> main ()
> {
>   extern foo ();

>   foo ("hello world!\n");
> }

> in a C Mode buffer.  Notice that the identifier in the declarator of
> `foo' is not fontified as a function.

> Emacs  : GNU Emacs 29.0.90 (build 1, x86_64-pc-linux-gnu)
>  of 2023-04-29
> Package: CC Mode 5.35.2 (C/*l)
> Buffer Style: gnu
> c-emacs-features: (pps-extended-state col-0-paren posix-char-classes gen-string-delim gen-comment-delim syntax-properties category-properties 1-bit)

[ .... ]

This was a special case which wasn't being handled.

Would you please try the attached patch on your real C code, and let me
know how well it works.  It should apply cleanly to either the emacs-29
branch or the trunk.

Thanks!

-- 
Alan Mackenzie (Nuremberg, Germany).