--- old/src/os_cpu/bsd_x86/vm/vmStructs_bsd_x86.hpp	2012-02-16 14:20:28.000000000 +0100
+++ new/src/os_cpu/bsd_x86/vm/vmStructs_bsd_x86.hpp	2012-02-16 14:20:28.000000000 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,12 +29,18 @@
 // constants required by the Serviceability Agent. This file is
 // referenced by vmStructs.cpp.
 
+#ifdef __APPLE__
+#define OS_THREAD_ID_TYPE thread_t
+#else
+#define OS_THREAD_ID_TYPE pthread_t
+#endif
+
 #define VM_STRUCTS_OS_CPU(nonstatic_field, static_field, unchecked_nonstatic_field, volatile_nonstatic_field, nonproduct_nonstatic_field, c2_nonstatic_field, unchecked_c1_static_field, unchecked_c2_static_field, last_entry) \
                                                                                                                                      \
   /******************************/                                                                                                   \
   /* Threads (NOTE: incomplete) */                                                                                                   \
   /******************************/                                                                                                   \
-  nonstatic_field(OSThread,                      _thread_id,                                      pthread_t)                             \
+  nonstatic_field(OSThread,                      _thread_id,                                      OS_THREAD_ID_TYPE)                 \
   nonstatic_field(OSThread,                      _pthread_id,                                     pthread_t)                         \
   /* This must be the last entry, and must be present */                                                                             \
   last_entry()
@@ -46,7 +52,7 @@
   /* Posix Thread IDs   */                                                \
   /**********************/                                                \
                                                                           \
-  declare_integer_type(pid_t)                                             \
+  declare_unsigned_integer_type(thread_t)                                 \
   declare_unsigned_integer_type(pthread_t)                                \
                                                                           \
   /* This must be the last entry, and must be present */                  \