Factor out get_pointer, supply an overload for std::auto_ptr.

[SVN r16672]

include/boost/get_pointer.hpp

@@ -0,0 +1,30 @@
+// Copyright Peter Dimov and David Abrahams 2002. Permission to copy,
+// use, modify, sell and distribute this software is granted provided
+// this copyright notice appears in all copies of the source. This
+// software is provided "as is" without express or implied warranty,
+// and with no claim as to its suitability for any purpose.
+#ifndef GET_POINTER_DWA20021219_HPP
+# define GET_POINTER_DWA20021219_HPP
+
+# include <memory>
+
+namespace boost { 
+
+// get_pointer(p) extracts a ->* capable pointer from p
+
+template<class T> T * get_pointer(T * p)
+{
+    return p;
+}
+
+// get_pointer(shared_ptr<T> const & p) has been moved to shared_ptr.hpp
+
+template<class T> T * get_pointer(std::auto_ptr<T> const& p)
+{
+    return p.get();
+}
+
+
+} // namespace boost
+
+#endif // GET_POINTER_DWA20021219_HPP