diff --git a/glib/giounix.c b/glib/giounix.c
index 72a3ed4df..5624ac9d0 100644
--- a/glib/giounix.c
+++ b/glib/giounix.c
@@ -454,7 +454,10 @@ g_io_channel_new_file (const gchar *filename,
     MODE_R = 1 << 0,
     MODE_W = 1 << 1,
     MODE_A = 1 << 2,
-    MODE_PLUS = 1 << 3
+    MODE_PLUS = 1 << 3,
+    MODE_R_PLUS = MODE_R | MODE_PLUS,
+    MODE_W_PLUS = MODE_W | MODE_PLUS,
+    MODE_A_PLUS = MODE_A | MODE_PLUS
   } mode_num;
   struct stat buffer;
 
@@ -505,15 +508,16 @@ g_io_channel_new_file (const gchar *filename,
       case MODE_A:
         flags = O_WRONLY | O_APPEND | O_CREAT;
         break;
-      case MODE_R | MODE_PLUS:
+      case MODE_R_PLUS:
         flags = O_RDWR;
         break;
-      case MODE_W | MODE_PLUS:
+      case MODE_W_PLUS:
         flags = O_RDWR | O_TRUNC | O_CREAT;
         break;
-      case MODE_A | MODE_PLUS:
+      case MODE_A_PLUS:
         flags = O_RDWR | O_APPEND | O_CREAT;
         break;
+      case MODE_PLUS:
       default:
         g_assert_not_reached ();
         flags = 0;
@@ -556,12 +560,13 @@ g_io_channel_new_file (const gchar *filename,
         channel->is_readable = FALSE;
         channel->is_writeable = TRUE;
         break;
-      case MODE_R | MODE_PLUS:
-      case MODE_W | MODE_PLUS:
-      case MODE_A | MODE_PLUS:
+      case MODE_R_PLUS:
+      case MODE_W_PLUS:
+      case MODE_A_PLUS:
         channel->is_readable = TRUE;
         channel->is_writeable = TRUE;
         break;
+      case MODE_PLUS:
       default:
         g_assert_not_reached ();
     }