diff --git a/include/stdex/stream.hpp b/include/stdex/stream.hpp
index 4bc3c2438..6e23c87be 100644
--- a/include/stdex/stream.hpp
+++ b/include/stdex/stream.hpp
@@ -2383,6 +2383,9 @@ namespace stdex
 			socket(_In_ const socket& other);
 			socket& operator =(_In_ const socket& other);
 
+			// Force use of valid() method when testing handle.
+			operator bool() const;
+
 		public:
 			socket(_Inout_ socket&& other) noexcept : m_h(other.m_h)
 			{
diff --git a/include/stdex/system.hpp b/include/stdex/system.hpp
index 43e64bdff..fa7aca56b 100644
--- a/include/stdex/system.hpp
+++ b/include/stdex/system.hpp
@@ -200,6 +200,10 @@ namespace stdex
 		///
 		operator T() const noexcept { return m_h; }
 
+	private:
+		// Force use of valid() method when testing handle.
+		operator bool() const;
+
 	protected:
 		T m_h;
 	};