imenu not working properly in cc-mode

imenu not working properly in cc-mode

[Joe Bloggs]

When I try to find a function using imenu in a c or c++ file containing several functions, 
emacs stops responding and starts eating all the cpu cycles.
If the c/c++ file has just a 'main' function it works but is a bit slow, and for R files
(in ESS mode) it seems to work fine.
What's going on, and how can I fix it? Anyone?

Re: imenu not working properly in cc-mode

[Alan Mackenzie]

Hi, Joe

Joe Bloggs <who@cares.invalid> wrote:
> When I try to find a function using imenu in a c or c++ file containing several functions, 
> emacs stops responding and starts eating all the cpu cycles.

> If the c/c++ file has just a 'main' function it works but is a bit slow, and for R files
> (in ESS mode) it seems to work fine.

> What's going on, and how can I fix it? Anyone?

OK, the C/C++ bit looks like mine, but I can't help you on R/ESS files,
whatever they might be.

So, first of all, could you provide a full bug report - basically a way
for somebody else to reproduce the problem.  It should be the sort of
recipe that a hyperactive 10 year old could follow.  Something like:

   Start Emacs with emacs -Q
   Load the file foo.c++ with C-x C-f /path/to/foo.c++
   Type M-x imenu <RET> bar <RET>
   Emacs hangs.

Please supply the file foo.c++, too.  Actually, if it happens in a C
file that would be easier to debug.  The smaller you can make this file,
the more it will be appreciated by the CC Mode maintainer (me).

If the bug happens from an Emacs without your own configurations, 

Also wanted is your CC Mode configuration: Just do C-c C-b from your
C/C++ buffer, and you get this in a template for the bug report.

VERSION NUMBERS ARE IMPORTANT!!!   M-x emacs-version and M-x c-version
will get them, but they'll be in the C-c C-b dump anyway.

Then send the thing to bug-cc-mode@gnu.org.

Look forward to hearing from you!

-- 
Alan Mackenzie (Nuremberg, Germany).