diff --git a/ChangeLog b/ChangeLog
index 7a011c21c4..07b8caf31d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Jul 29 06:54:30 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* win32/win32.c (rb_w32_pipe): use enum for compile time constants,
+	  instead of const int for debugging.
+
 Mon Jul 29 00:11:49 2013  Tanaka Akira  <akr@fsij.org>
 
 	* bignum.c (bigdivrem): Specialized implementation added for
diff --git a/win32/win32.c b/win32/win32.c
index 55a73b4056..0a03d7bcca 100644
--- a/win32/win32.c
+++ b/win32/win32.c
@@ -5655,10 +5655,12 @@ rb_w32_pipe(int fds[2])
 {
     static DWORD serial = 0;
     static const char prefix[] = "\\\\.\\pipe\\ruby";
-    const int width_of_prefix = (int)sizeof(prefix) - 1;
-    const int width_of_pid = (int)sizeof(rb_pid_t) * 2;
-    const int width_of_serial = (int)sizeof(serial) * 2;
-    const int width_of_ids = width_of_pid + 1 + width_of_serial + 1;
+    enum {
+	width_of_prefix = (int)sizeof(prefix) - 1,
+	width_of_pid = (int)sizeof(rb_pid_t) * 2,
+	width_of_serial = (int)sizeof(serial) * 2,
+	width_of_ids = width_of_pid + 1 + width_of_serial + 1
+    };
     char name[sizeof(prefix) + width_of_ids];
     SECURITY_ATTRIBUTES sec;
     HANDLE hRead, hWrite, h;