diff --git a/bson/oid.h b/bson/oid.h
index bf06ee1..fdee537 100644
--- a/bson/oid.h
+++ b/bson/oid.h
@@ -88,6 +88,7 @@ namespace mongo {
         };
         static MachineAndPid ourMachine, ourMachineAndPid;
         union {
+            unsigned char data[12];
             struct {
                 // 12 bytes total
                 unsigned char _time[4];
@@ -98,7 +99,6 @@ namespace mongo {
                 long long a;
                 unsigned b;
             };
-            unsigned char data[12];
         };
 
         static unsigned ourPid();