diff --git a/Foundation/src/Event_POSIX.cpp b/Foundation/src/Event_POSIX.cpp
index 4d7cd2367..d2fc8c0f5 100644
--- a/Foundation/src/Event_POSIX.cpp
+++ b/Foundation/src/Event_POSIX.cpp
@@ -24,6 +24,19 @@
 #endif
 
 
+//
+// Note: pthread_cond_timedwait() with CLOCK_MONOTONIC is supported
+// on Linux and QNX, as well as on Android >= 5.0. On Android < 5.0,
+// HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC is defined to indicate 
+// availability of non-standard pthread_cond_timedwait_monotonic().
+//
+#ifndef POCO_HAVE_MONOTONIC_PTHREAD_COND_TIMEDWAIT
+#if (defined(__linux__) || defined(__QNX__)) && !(defined(__ANDROID__) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC))
+#define POCO_HAVE_MONOTONIC_PTHREAD_COND_TIMEDWAIT 1
+#endif
+#endif
+
+
 namespace Poco {
 
 
@@ -40,7 +53,7 @@ EventImpl::EventImpl(EventTypeImpl type): _auto(type == EVENT_AUTORESET_IMPL), _
 	if (pthread_mutex_init(&_mutex, NULL))
 		throw SystemException("cannot create event (mutex)");
 
-#if defined(__linux__) || defined(__QNX__)
+#if defined(POCO_HAVE_MONOTONIC_PTHREAD_COND_TIMEDWAIT)
 	pthread_condattr_t attr;
 	if (pthread_condattr_init(&attr))
 	{
@@ -105,7 +118,7 @@ bool EventImpl::waitImpl(long milliseconds)
 	delta.tv_sec  = milliseconds / 1000;
 	delta.tv_nsec = (milliseconds % 1000)*1000000;
 	pthread_get_expiration_np(&delta, &abstime);
-#elif defined(__linux__) || defined(__QNX__)
+#elif defined(POCO_HAVE_MONOTONIC_PTHREAD_COND_TIMEDWAIT)
 	clock_gettime(CLOCK_MONOTONIC, &abstime);
 	abstime.tv_sec  += milliseconds / 1000;
 	abstime.tv_nsec += (milliseconds % 1000)*1000000;
diff --git a/Foundation/src/Semaphore_POSIX.cpp b/Foundation/src/Semaphore_POSIX.cpp
index 88e768ed1..57c5dae15 100644
--- a/Foundation/src/Semaphore_POSIX.cpp
+++ b/Foundation/src/Semaphore_POSIX.cpp
@@ -24,6 +24,19 @@
 #endif
 
 
+//
+// Note: pthread_cond_timedwait() with CLOCK_MONOTONIC is supported
+// on Linux and QNX, as well as on Android >= 5.0. On Android < 5.0,
+// HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC is defined to indicate 
+// availability of non-standard pthread_cond_timedwait_monotonic().
+//
+#ifndef POCO_HAVE_MONOTONIC_PTHREAD_COND_TIMEDWAIT
+#if (defined(__linux__) || defined(__QNX__)) && !(defined(__ANDROID__) && defined(HAVE_PTHREAD_COND_TIMEDWAIT_MONOTONIC))
+#define POCO_HAVE_MONOTONIC_PTHREAD_COND_TIMEDWAIT 1
+#endif
+#endif
+
+
 namespace Poco {
 
 
@@ -41,7 +54,7 @@ SemaphoreImpl::SemaphoreImpl(int n, int max): _n(n), _max(max)
 	if (pthread_mutex_init(&_mutex, NULL))
 		throw SystemException("cannot create semaphore (mutex)");
 
-#if defined(__linux__) || defined(__QNX__)
+#if defined(POCO_HAVE_MONOTONIC_PTHREAD_COND_TIMEDWAIT)
 	pthread_condattr_t attr;
 	if (pthread_condattr_init(&attr))
 	{
@@ -105,7 +118,7 @@ bool SemaphoreImpl::waitImpl(long milliseconds)
 	delta.tv_sec  = milliseconds / 1000;
 	delta.tv_nsec = (milliseconds % 1000)*1000000;
 	pthread_get_expiration_np(&delta, &abstime);
-#elif defined(__linux__) || defined(__QNX__)
+#elif defined(POCO_HAVE_MONOTONIC_PTHREAD_COND_TIMEDWAIT)
 	clock_gettime(CLOCK_MONOTONIC, &abstime);
 	abstime.tv_sec  += milliseconds / 1000;
 	abstime.tv_nsec += (milliseconds % 1000)*1000000;