gistfile1.diff

diff --git a/ext/rubymain.cpp b/ext/rubymain.cpp
index 1e0dd6f..4eb7738 100644
--- a/ext/rubymain.cpp
+++ b/ext/rubymain.cpp
@@ -33,24 +33,36 @@ static VALUE EmConnection;
 static VALUE Intern_at_signature;
 static VALUE Intern_at_timers;
 static VALUE Intern_at_conns;
+static VALUE Intern_at_error_handler;
 static VALUE Intern_event_callback;
 static VALUE Intern_run_deferred_callbacks;
 static VALUE Intern_delete;
 static VALUE Intern_call;
 static VALUE Intern_receive_data;
 static VALUE Intern_ssl_handshake_completed;
-
 static VALUE Intern_notify_readable;
 static VALUE Intern_notify_writable;
 
 static VALUE rb_cProcStatus;
 
+struct em_event {
+	const char *a1;
+	int a2;
+	const char *a3;
+	int a4;
+};
+
 /****************
 t_event_callback
 ****************/
 
-static void event_callback (const char *a1, int a2, const char *a3, int a4)
+static void event_callback (struct em_event* e)
 {
+	const char *a1 = e->a1;
+	int a2 = e->a2;
+	const char *a3 = e->a3;
+	int a4 = e->a4;
+
 	if (a2 == EM_CONNECTION_READ) {
 		VALUE t = rb_ivar_get (EmModule, Intern_at_conns);
 		VALUE q = rb_hash_aref (t, rb_str_new2(a1));
@@ -93,7 +105,33 @@ static void event_callback (const char *a1, int a2, const char *a3, int a4)
 		rb_funcall (EmModule, Intern_event_callback, 3, rb_str_new2(a1), (a2 << 1) | 1, rb_str_new(a3,a4));
 }
 
+/*******************
+event_error_handler
+*******************/
+
+static void event_error_handler(void *, VALUE err)
+{
+	VALUE error_handler = rb_ivar_get(EmModule, Intern_at_error_handler);
+	rb_funcall (error_handler, Intern_call, 1, err);
+}
+
+/**********************
+event_callback_wrapper
+**********************/
 
+static void event_callback_wrapper (const char *a1, int a2, const char *a3, int a4)
+{
+	struct em_event e;
+	e.a1 = a1;
+	e.a2 = a2;
+	e.a3 = a3;
+	e.a4 = a4;
+
+	if (!rb_ivar_defined(EmModule, Intern_at_error_handler))
+		event_callback(&e);
+	else
+		rb_rescue((VALUE (*)(ANYARGS))event_callback, (VALUE)&e, (VALUE (*)(ANYARGS))event_error_handler, NULL);
+}
 
 /**************************
 t_initialize_event_machine
@@ -101,7 +139,7 @@ t_initialize_event_machine
 
 static VALUE t_initialize_event_machine (VALUE self)
 {
-	evma_initialize_library (event_callback);
+	evma_initialize_library (event_callback_wrapper);
 	return Qnil;
 }
 
@@ -703,6 +741,7 @@ extern "C" void Init_rubyeventmachine()
 	Intern_at_signature = rb_intern ("@signature");
 	Intern_at_timers = rb_intern ("@timers");
 	Intern_at_conns = rb_intern ("@conns");
+	Intern_at_error_handler = rb_intern("@error_handler");
 
 	Intern_event_callback = rb_intern ("event_callback");
 	Intern_run_deferred_callbacks = rb_intern ("run_deferred_callbacks");
@@ -710,7 +749,6 @@ extern "C" void Init_rubyeventmachine()
 	Intern_call = rb_intern ("call");
 	Intern_receive_data = rb_intern ("receive_data");
 	Intern_ssl_handshake_completed = rb_intern ("ssl_handshake_completed");
-
 	Intern_notify_readable = rb_intern ("notify_readable");
 	Intern_notify_writable = rb_intern ("notify_writable");
 
diff --git a/lib/eventmachine.rb b/lib/eventmachine.rb
index d355e1b..f9b415d 100644
--- a/lib/eventmachine.rb
+++ b/lib/eventmachine.rb
@@ -1165,7 +1165,19 @@ module EventMachine
 		c
 	end
 
-
+	# Catch-all for errors raised during event loop callbacks.
+	#
+	# EM.error_handler{ |e|
+	#   puts "Error raised during event loop: #{e.message}"
+	# }
+	#
+	def EventMachine::error_handler cb = nil, &blk
+		if cb or blk
+			@error_handler = cb || blk
+		elsif instance_variable_defined? :@error_handler
+			remove_instance_variable :@error_handler
+		end
+	end
 
 	private
 	def EventMachine::event_callback conn_binding, opcode, data
diff --git a/tasks/tests.rake b/tasks/tests.rake
index 81f3dea..af575b6 100644
--- a/tasks/tests.rake
+++ b/tasks/tests.rake
@@ -37,6 +37,7 @@ namespace :test do
       "test_basic.rb",
       "test_epoll.rb",
       "test_errors.rb",
+      "test_error_handler.rb",
       "test_eventables.rb",
       "test_exc.rb",
       "test_futures.rb",
diff --git a/tests/test_error_handler.rb b/tests/test_error_handler.rb
new file mode 100644
index 0000000..0bc9432
--- /dev/null
+++ b/tests/test_error_handler.rb
@@ -0,0 +1,32 @@
+$:.unshift "../lib"
+require 'eventmachine'
+require 'test/unit'
+
+class TestErrorHandler < Test::Unit::TestCase
+  def test_error_handler
+    error = nil
+    EM.error_handler{ |e|
+      error = e
+      EM.error_handler(nil)
+      EM.stop
+    }
+
+    EM.run{
+      EM.add_timer(0){
+        raise 'test'
+      }
+    }
+
+    assert_equal error.message, 'test'
+  end
+
+  def test_without_error_handler
+    assert_raise RuntimeError do
+      EM.run{
+        EM.add_timer(0){
+          raise 'test'
+        }
+      }
+    end
+  end
+end