1 files changed, 19 insertions, 0 deletions
diff --git a/src/mscorlib/shared/System/IO/FileStream.OSX.cs b/src/mscorlib/shared/System/IO/FileStream.OSX.cs
new file mode 100644
index 0000000000..f29e922337
--- /dev/null
+++ b/src/mscorlib/shared/System/IO/FileStream.OSX.cs
@@ -0,0 +1,19 @@
+// 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.
+
+namespace System.IO
+{
+    public partial class FileStream : Stream
+    {
+        private void LockInternal(long position, long length)
+        {
+            throw new PlatformNotSupportedException(SR.PlatformNotSupported_OSXFileLocking);
+        }
+
+        private void UnlockInternal(long position, long length)
+        {
+            throw new PlatformNotSupportedException(SR.PlatformNotSupported_OSXFileLocking);
+        }
+    }
+}