diff --git a/include/boost/asio/buffer.hpp b/include/boost/asio/buffer.hpp
index ff28fa58..eec06c42 100644
--- a/include/boost/asio/buffer.hpp
+++ b/include/boost/asio/buffer.hpp
@@ -393,7 +393,12 @@ public:
 
   ~buffer_debug_check()
   {
+#if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
+    // MSVC's string iterator checking may crash in a std::string::iterator
+    // object's destructor when the iterator points to an already-destroyed
+    // std::string object, unless the iterator is cleared first.
     iter_ = Iterator();
+#endif // BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
   }
 
   void operator()()
diff --git a/include/boost/asio/detail/old_win_sdk_compat.hpp b/include/boost/asio/detail/old_win_sdk_compat.hpp
index 1daacacc..707177bb 100644
--- a/include/boost/asio/detail/old_win_sdk_compat.hpp
+++ b/include/boost/asio/detail/old_win_sdk_compat.hpp
@@ -31,6 +31,10 @@
 #if defined(BOOST_ASIO_HAS_OLD_WIN_SDK)
 
 // Emulation of types that are missing from old Platform SDKs.
+//
+// N.B. this emulation is also used if building for a Windows 2000 target with
+// a recent (i.e. Vista or later) SDK, as the SDK does not provide IPv6 support
+// in that case.
 
 namespace boost {
 namespace asio {
@@ -55,9 +59,19 @@ struct sockaddr_storage_emulation
 
 struct in6_addr_emulation
 {
-  u_char s6_addr[16];
+  union
+  {
+    u_char Byte[16];
+    u_short Word[8];
+  } u;
 };
 
+#if !defined(s6_addr)
+# define _S6_un u
+# define _S6_u8 Byte
+# define s6_addr _S6_un._S6_u8
+#endif // !defined(s6_addr)
+
 struct sockaddr_in6_emulation
 {
   short sin6_family;
diff --git a/include/boost/asio/detail/socket_ops.hpp b/include/boost/asio/detail/socket_ops.hpp
index af285bee..5a346c65 100644
--- a/include/boost/asio/detail/socket_ops.hpp
+++ b/include/boost/asio/detail/socket_ops.hpp
@@ -1825,7 +1825,8 @@ inline boost::system::error_code getnameinfo(const socket_addr_type* addr,
     if (gni_t gni = (gni_t)::GetProcAddress(winsock_module, "getnameinfo"))
     {
       clear_error(ec);
-      int error = gni(addr, addrlen, host, static_cast<DWORD>(hostlen),
+      int error = gni(addr, static_cast<int>(addrlen),
+          host, static_cast<DWORD>(hostlen),
           serv, static_cast<DWORD>(servlen), flags);
       return ec = translate_addrinfo_error(error);
     }