How do you like this feature to be implemented? Do you have a single occurrence
of a string you want to look for or will this string occur multiple times?

I'm just wondering if it isn't better to have this feature in a new plug-in (or
two, see below). Currently I'm scanning a set of workspace files, group them by
package/project and show the tasks by priority and file.

I see the following two requirements:

1.) In our project we have the requirement to fail a build, if the build log
contains the string ERROR. So maybe I should add a special priority ERROR to the
tasks plugin to fail the build if the log (or any of the workspace files)
contains a regexp? Or do you just need the references of the found texts and no
failure?

2.) What I'm planning anyway is to create a new plug-in that scans the build log
for (Java) compiler warnings that works in the same way as my other plugins.
Maybe this will be a better extension point for your C compiler warnings.

1) Requirement is already provided by text scanner plugin.

2.) Answer from gbr4:

I was specifically looking for a way to flag any compiler or other toolchain
warnings as tasks to be addressed. There would be multiple occurrences of these
warnings. To make things slightly more complicated I am using matrix builds, so
I would want this log parsed:
https://hudson.idm.cit.cornell.edu/hudson/job/cuwal2/90/APVer=2.2.8,label=Linux-RHEL4/console

not this one:
https://hudson.idm.cit.cornell.edu/hudson/job/cuwal2/90/console

What I've done so far is to pipe the output of make through tee and run task
scanner on the resulting log. That sort of works but is ugly. And the tasks flag
the log instead of the files that need to be fixed.

The other thing is the warning format is usually very standard:
filename:line: warning: message

If there were a way to have task scanner highlight the line of source that
caused the warning instead of the line of the log that would be great. Here are
two example warnings.

/users/idmbuild/local/httpd-2.2.8/build/libtool --silent --mode=compile gcc
-prefer-pic -DLINUX=2 -D_REENTRANT -D_GNU_SOURCE -D_LARGEFILE64_SOURCE -g -O2
-pthread -I/users/idmbuild/local/httpd-2.2.8/include
-I/users/idmbuild/local/httpd-2.2.8/include
-I/users/idmbuild/local/httpd-2.2.8/include -g -Wall -I./test_restore/ -I./
-I.. -I../log -I../config2 -I../apache -I../util -I../cred -I../permit
-I../session -I../pal -I../sha1 -I../highAvail
-I/users/idmbuild/local/krb5-1.6.3/include
-I/users/idmbuild/local/openssl-0.9.8g/include -DHAVE_SSL -DAPACHE_BUILD -c -o
cuwl_html.lo cuwl_html.c && touch cuwl_html.slo
cuwl_html.c: In function `cuwl_send_response':
cuwl_html.c:119: warning: implicit declaration of function `ap_rprintf'

/users/idmbuild/local/httpd-2.2.8/build/libtool --silent --mode=compile gcc
-prefer-pic -DLINUX=2 -D_REENTRANT -D_GNU_SOURCE -D_LARGEFILE64_SOURCE -g -O2
-pthread -I/users/idmbuild/local/httpd-2.2.8/include
-I/users/idmbuild/local/httpd-2.2.8/include
-I/users/idmbuild/local/httpd-2.2.8/include -g -Wall -I./ -I.. -I../log
-I../config2 -I../apache -I../util -I../cred -I../permit -I../session -I../pal
-I../sha1 -I../highAvail -I/users/idmbuild/local/krb5-1.6.3/include
-I/users/idmbuild/local/openssl-0.9.8g/include -DAPACHE_BUILD -DHAVE_SSL -c -o
../apache/session_bucket.lo ../apache/session_bucket.c && touch
../apache/session_bucket.slo
../apache/session_bucket.c:121: warning: initialization from incompatible
pointer type

I created a new plug-in: warnings. This scans the build log for compiler
warnings. Currently, parsing support is available for javac and hpi compile.

Writing a C parser shouldn't be a problem. Are you interesting in providing this
part of the implementation?

The new pluing is released. Please use
https://hudson.dev.java.net/issues/show_bug.cgi?id=1688 to request compiler parsers.