Grep exits abnormally with code 123 when running rgrep on emacs

Question

Greetings fellow Emacsers

I'm running GNU Emacs 23.1.1 on "Ubuntu 10.04.1 LTS" and any search I perform using the built-in M-x rgrep on the standard Linux kernel source code (vanilla) ends prematurely with the following error printed to the emacs echo area:

Grep exited abnormally with code 123

I have been seeing it for a while on Redhat systems as well, and with other (large) code bases, Anybody seen or even better cured that?

Thanks!

Edit: for reasons beyond me stackexchange does not allow me to edit my comment below so I'll update here.

following the comment below I have tried to run the same command that rgrep runs in an emacs shell buffer

 find . \( -path \*/SCCS -o -path \*/RCS -o -path \*/CVS -o -path \*/MCVS -o -path \*/.svn -o -path \*/.git
-o -path \*/.hg -o -path \*/.bzr -o -path \*/_MTN -o -path \*/_darcs -o -path \*/\{arch\} \) -prune -o  -type f \( -name \*.\[ch\] \) -p
rint0 | xargs -0 -e grep -i -nH -e v4l_compat_ioctl32

while it does not print any error, interrogating the exit code shows the same 123 again.

/home/mcradle/linux> echo $?
123

following the comment from Gilles I've tried to run

/home/mcradle/linux> find . -type f \( -name \*.\[ch\] \) -exec grep -i -nH -e v4l_compat_ioctl32 '{}' \;

which is functionally equivalent to the find and xargs combination and it completed with exit code 0

/home/mcradle/linux> echo $?
0

so it does seems to be something with xargs.

Answer 1

Looking at xargs exit code documentation:

123 if any invocation of the command exited with status 1-125

but according to grep documentation 1 is the exit status if grep didn't match the pattern

EXIT STATUS
   Normally, the exit status is 0 if selected lines are found and 1 otherwise.  

So to me it seems that the command line that emacs uses to issue an 'rgrep' search will always return 123, and this error either needs to be suppressed or replaced with a command line such as

find . -type f \( -name \*.\[ch\] \) -exec grep -i -nH -e v4l

Answer 2

It looks like you're trying to do a recursive grep through a bunch of C .c and .h files, while ignoring directories used by version control systems. You want ack. See http://betterthangrep.com/

The command to do exactly what you are doing, in ack:

ack --cc -i v4l_compat_ioctl32

The effects of -r, -n and -H are assumed in ack. The -i is still case-insensitive, and --cc says "Search *.c and *.h files only"

No need for find. No need for xargs. Just a version of Perl installed and a single Perl program, with no external modules.