diff --git a/cwThread.cpp b/cwThread.cpp
index 7a923e0..78222a1 100644
--- a/cwThread.cpp
+++ b/cwThread.cpp
@@ -204,8 +204,21 @@ cw::thread::stateId_t cw::thread::state( handle_t h )
   return p->stateId;
 }
 
-unsigned cw::thread::id()
-{ return static_cast<unsigned>(pthread_self()); }
+cw::thread::thread_id_t cw::thread::id()
+{
+  typedef struct
+  {
+    union
+    {
+      thread_id_t id;
+      pthread_t   pthread_id;
+    } u;
+  } id_t;
+  
+  id_t id;
+  id.u.pthread_id = pthread_self();
+  return id.u.id;
+}
 
 namespace cw
 {
diff --git a/cwThread.h b/cwThread.h
index 0b119f0..287dbc8 100644
--- a/cwThread.h
+++ b/cwThread.h
@@ -17,6 +17,8 @@ namespace cw
 
     typedef bool (*cbFunc_t)( void* arg );
 
+    typedef  unsigned long long thread_id_t;
+
     // stateMicros = total time out duration for switching to the  exit state or for switching in/out of pause state. 
     // pauseMicros = duration of thread sleep interval when in paused state.
     rc_t create( handle_t& hRef, cbFunc_t func, void* funcArg, int stateTimeOutMicros=100000, int pauseMicros=10000 );
@@ -30,7 +32,7 @@ namespace cw
     stateId_t state( handle_t h );
 
     // Return the thread id of the calling context.
-    unsigned id();
+    thread_id_t id();
   }
   rc_t threadTest();
 }