diff --git a/ChangeLog b/ChangeLog
index 77e46c87c0..3aeb07a55f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+Fri May 30 22:28:03 2008  Yusuke Endoh  <mame@tsg.ne.jp>
+
+	* signal.c (esignal_signo): fix SignalException#signo which returned
+	  nil absolutely.
+
+	* signal.c (esignal_init): always prepend "SIG" to a string that is
+	  returned by SignalException#signm.
+
 Fri May 30 22:17:39 2008  Yusuke Endoh  <mame@tsg.ne.jp>
 
 	* test/ruby/test_argf.rb: rename a conflicting method name.
diff --git a/signal.c b/signal.c
index 65e35a062f..0915b6a063 100644
--- a/signal.c
+++ b/signal.c
@@ -253,9 +253,7 @@ esignal_init(int argc, VALUE *argv, VALUE self)
 	if (!signo) {
 	    rb_raise(rb_eArgError, "unsupported name `SIG%s'", signm);
 	}
-	if (SYMBOL_P(sig)) {
-	    sig = rb_str_new2(signm);
-	}
+	sig = rb_sprintf("SIG%s", signm);
     }
     rb_call_super(1, &sig);
     rb_iv_set(self, "signo", INT2NUM(signo));
@@ -263,6 +261,19 @@ esignal_init(int argc, VALUE *argv, VALUE self)
     return self;
 }
 
+/*
+ * call-seq:
+ *    signal_exception.signo   =>  num
+ *
+ *  Returns a signal number.
+ */
+
+static VALUE
+esignal_signo(VALUE self)
+{
+    return rb_iv_get(self, "signo");
+}
+
 static VALUE
 interrupt_init(int argc, VALUE *argv, VALUE self)
 {
@@ -1070,7 +1081,7 @@ Init_signal(void)
     rb_define_module_function(mSignal, "list", sig_list, 0);
 
     rb_define_method(rb_eSignal, "initialize", esignal_init, -1);
-    rb_attr(rb_eSignal, rb_intern("signo"), 1, 0, 0);
+    rb_define_method(rb_eSignal, "signo", esignal_signo, 0);
     rb_alias(rb_eSignal, rb_intern("signm"), rb_intern("message"));
     rb_define_method(rb_eInterrupt, "initialize", interrupt_init, -1);