diff --git a/include/boost/thread/exceptions.hpp b/include/boost/thread/exceptions.hpp
index 9b4e9f93..45cf191f 100644
--- a/include/boost/thread/exceptions.hpp
+++ b/include/boost/thread/exceptions.hpp
@@ -34,7 +34,7 @@ protected:
 public:
     ~thread_exception() throw();
 
-    int native_error() const { return m_sys_err; }
+    int native_error() const;
 
     const char* message() const;
 
diff --git a/src/exceptions.cpp b/src/exceptions.cpp
index 89e0b167..766a9387 100644
--- a/src/exceptions.cpp
+++ b/src/exceptions.cpp
@@ -82,6 +82,11 @@ thread_exception::~thread_exception() throw()
 {
 }
 
+int thread_exception::native_error() const
+{
+    return m_sys_err; 
+}
+
 const char* thread_exception::message() const
 {
     if (m_sys_err != 0)