diff --git a/ChangeLog b/ChangeLog
index dba91a47d7..4d6f8acd02 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Feb 22 23:50:26 2005  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* signal.c (ruby_signal, ruby_nativethread_signal): must be valid as
+	  expressions, not only statements.
+
 Tue Feb 22 07:24:57 2005  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* parse.y (parser_yylex): identifier after dot must not be a variable.
diff --git a/signal.c b/signal.c
index 000fa5a0c2..63cb18cb49 100644
--- a/signal.c
+++ b/signal.c
@@ -386,9 +386,19 @@ posix_nativethread_signal(signum, handler)
 }
 #endif
 #else /* !POSIX_SIGNAL */
-#define ruby_signal(sig,handler) {rb_trap_accept_nativethreads[sig] = 0; signal((sig),(handler));}
+#define ruby_signal(sig,handler) (rb_trap_accept_nativethreads[sig] = 0, signal((sig),(handler)))
 #ifdef HAVE_NATIVETHREAD
-#define ruby_nativethread_signal(sig,handler) {signal((sig),(handler));rb_trap_accept_nativethreads[sig] = 1;}
+static sighandler_t
+ruby_nativethread_signal(signum, handler)
+    int signum;
+    sighandler_t handler;
+{
+    sighandler_t old;
+
+    old = signal(signum, handler);
+    rb_trap_accept_nativethreads[signum] = 1;
+    return old;
+}
 #endif
 #endif