diff --git a/include/boost/thread/pthread/mutex.hpp b/include/boost/thread/pthread/mutex.hpp
index 3e9af2a83..601c87e47 100644
--- a/include/boost/thread/pthread/mutex.hpp
+++ b/include/boost/thread/pthread/mutex.hpp
@@ -27,7 +27,7 @@
 #include <boost/thread/detail/delete.hpp>
 
 #ifdef _POSIX_TIMEOUTS
-#if _POSIX_TIMEOUTS >= 0 && _POSIX_TIMEOUTS>=200112L
+#if (_POSIX_TIMEOUTS - 0) >= 200112L
 #ifndef BOOST_PTHREAD_HAS_TIMEDLOCK
 #define BOOST_PTHREAD_HAS_TIMEDLOCK
 #endif
diff --git a/include/boost/thread/pthread/recursive_mutex.hpp b/include/boost/thread/pthread/recursive_mutex.hpp
index 9330d77de..09d0f10a6 100644
--- a/include/boost/thread/pthread/recursive_mutex.hpp
+++ b/include/boost/thread/pthread/recursive_mutex.hpp
@@ -28,7 +28,7 @@
 #include <boost/thread/detail/delete.hpp>
 
 #ifdef _POSIX_TIMEOUTS
-#if _POSIX_TIMEOUTS >= 0 && _POSIX_TIMEOUTS>=200112L
+#if (_POSIX_TIMEOUTS - 0) >= 200112L
 #ifndef BOOST_PTHREAD_HAS_TIMEDLOCK
 #define BOOST_PTHREAD_HAS_TIMEDLOCK
 #endif