diff --git a/Foundation/src/DirectoryWatcher.cpp b/Foundation/src/DirectoryWatcher.cpp
index e51191609..897fb9722 100644
--- a/Foundation/src/DirectoryWatcher.cpp
+++ b/Foundation/src/DirectoryWatcher.cpp
@@ -53,6 +53,9 @@
 	#include <sys/types.h>
 	#include <sys/event.h>
 	#include <sys/time.h>
+	#if POCO_OS == POCO_OS_FREE_BSD
+		#define O_EVTONLY 0x8000
+	#endif
 #endif
 #include <algorithm>
 #include <map>