--- boost/asio/ip/detail/socket_option.hpp	(revision 49856)
+++ boost/asio/ip/detail/socket_option.hpp	(working copy)
@@ -41,7 +41,7 @@
 #if defined(__sun) || defined(__osf__)
   typedef unsigned char ipv4_value_type;
   typedef unsigned char ipv6_value_type;
-#elif defined(_AIX) || defined(__hpux)
+#elif defined(_AIX) || defined(__hpux) || defined(__QNXNTO__)
   typedef unsigned char ipv4_value_type;
   typedef unsigned int ipv6_value_type;
 #else