diff --git a/Rakefile b/Rakefile
index bce655c..c881f1d 100644
--- a/Rakefile
+++ b/Rakefile
@@ -297,7 +297,7 @@ BEGIN {
 
 # discover full path to this ruby executable
 #
-  c = Config::CONFIG
+  c = ::RbConfig::CONFIG
   bindir = c["bindir"] || c['BINDIR']
   ruby_install_name = c['ruby_install_name'] || c['RUBY_INSTALL_NAME'] || 'ruby'
   ruby_ext = c['EXEEXT'] || ''
diff --git a/lib/systemu.rb b/lib/systemu.rb
index aa12fe4..4f8bf5c 100644
--- a/lib/systemu.rb
+++ b/lib/systemu.rb
@@ -50,10 +50,50 @@ def quote(*words)
     end
   end
 
+  ##
+  # Class for returning the result of a systemu invocation
+  #
+  # This will contain at least a member +status+ containing a Process::Status
+  # object representing the result of the subprocess invocation. If a block was
+  # passed for parallel execution in a separate thread, this thread's instance
+  # object will be stored as member +thread+.
+  #
+  # In general this class is intended as a thin wrapper around the
+  # Process::Status instance it contains. Any access other than to the +thread+
+  # member will be forwared to the +status+ object.
+  class Result
+    attr_reader(:status)
+    attr_reader(:thread)
+
+    def initialize(status, thread = nil)
+      @status = status
+      @thread = thread
+    end
+
+    def ==(arg)
+      case arg
+      when Integer
+        @status == arg
+      when Result
+        (@status == arg.status) && (@thread == arg.thread)
+      else
+        raise "No comparison between SystemU::Result and #{arg.class}"
+      end
+    end
+
+    def method_missing(sym, *args)
+      @status.send(sym, *args)
+    end
+
+    def to_s
+      @status.to_s
+    end
+  end
+
+
 #
 # instance methods
 #
-
   def initialize argv, opts = {}, &block
     getopt = getopts opts
 
@@ -101,17 +141,10 @@ def systemu
             pipe.read rescue nil
           end
         }
-        status = $?
+        status = Result.new($?)
       ensure
         if thread
-          begin
-            class << status
-              attr 'thread'
-            end
-            status.instance_eval{ @thread = thread }
-          rescue
-            42
-          end
+          status = Result.new($?, thread)
         end
       end
 
@@ -294,10 +327,13 @@ def systemu
       field = process.get_class.get_declared_field("pid")
       field.set_accessible(true)
       pid = field.get(process)
-      _thread = new_thread pid, @block if @block
+      thread = new_thread pid, @block if @block
       exit_code = process.wait_for
       [
-        RubyProcess::RubyStatus.new_process_status(JRuby.runtime, exit_code, pid),
+        Result.new(
+          RubyProcess::RubyStatus.new_process_status(JRuby.runtime, exit_code, pid),
+          thread
+        ),
         stdout.join,
         stderr.join
       ]
diff --git a/test/systemu_test.rb b/test/systemu_test.rb
index 6d4bf2b..078b05a 100644
--- a/test/systemu_test.rb
+++ b/test/systemu_test.rb
@@ -31,6 +31,21 @@
     end
   end
 
+  testing 'invoke systemu with a block' do
+    res = systemu("sleep 0.1") { puts('Waiting') }
+    assert { res[1].instance_of?(String) }
+    assert { res[2].instance_of?(String) }
+    res = res[0]
+    assert { (res & 0xFFFF) == 0 }
+    assert { res == 0 }
+    assert { res.exited? }
+    assert { res.exitstatus == 0 }
+    assert { res.pid.instance_of?(Integer) }
+    assert { !res.signaled? }
+    assert { res.success? }
+    assert { res.to_i == 0 }
+    assert { res.to_s =~ /^pid \d+ exit 0$/ }
+  end
 end