1 files changed, 38 insertions, 0 deletions
diff --git a/src/mscorlib/shared/System/IO/FileMode.cs b/src/mscorlib/shared/System/IO/FileMode.cs
new file mode 100644
index 0000000000..77f2fe6f20
--- /dev/null
+++ b/src/mscorlib/shared/System/IO/FileMode.cs
@@ -0,0 +1,38 @@
+// 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
+{
+    // Contains constants for specifying how the OS should open a file.
+    // These will control whether you overwrite a file, open an existing
+    // file, or some combination thereof.
+    // 
+    // To append to a file, use Append (which maps to OpenOrCreate then we seek
+    // to the end of the file).  To truncate a file or create it if it doesn't 
+    // exist, use Create.
+    // 
+    public enum FileMode
+    {
+        // Creates a new file. An exception is raised if the file already exists.
+        CreateNew = 1,
+
+        // Creates a new file. If the file already exists, it is overwritten.
+        Create = 2,
+
+        // Opens an existing file. An exception is raised if the file does not exist.
+        Open = 3,
+
+        // Opens the file if it exists. Otherwise, creates a new file.
+        OpenOrCreate = 4,
+
+        // Opens an existing file. Once opened, the file is truncated so that its
+        // size is zero bytes. The calling process must open the file with at least
+        // WRITE access. An exception is raised if the file does not exist.
+        Truncate = 5,
+
+        // Opens the file if it exists and seeks to the end.  Otherwise, 
+        // creates a new file.
+        Append = 6,
+    }
+}