1 files changed, 20 insertions, 0 deletions
diff --git a/src/mscorlib/shared/Microsoft/Win32/SafeHandles/CriticalHandleZeroOrMinusOneIsInvalid.cs b/src/mscorlib/shared/Microsoft/Win32/SafeHandles/CriticalHandleZeroOrMinusOneIsInvalid.cs
new file mode 100644
index 0000000000..195e48df76
--- /dev/null
+++ b/src/mscorlib/shared/Microsoft/Win32/SafeHandles/CriticalHandleZeroOrMinusOneIsInvalid.cs
@@ -0,0 +1,20 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Runtime.InteropServices;
+
+namespace Microsoft.Win32.SafeHandles
+{
+    // Class of critical handle which uses 0 or -1 as an invalid handle.
+    public abstract class CriticalHandleZeroOrMinusOneIsInvalid : CriticalHandle
+    {
+        protected CriticalHandleZeroOrMinusOneIsInvalid()
+            : base(IntPtr.Zero)
+        {
+        }
+
+        public override bool IsInvalid => handle.IsNull() || handle == new IntPtr(-1);
+    }
+}