diff --git a/Source/OpenTK/OpenAL/AlcFunctions.cs b/Source/OpenTK/OpenAL/AlcFunctions.cs
index 358ed75a..ec17db33 100644
--- a/Source/OpenTK/OpenAL/AlcFunctions.cs
+++ b/Source/OpenTK/OpenAL/AlcFunctions.cs
@@ -114,6 +114,7 @@ namespace OpenTK.OpenAL
         /// <param name="context">A pointer to the new context.</param>
         /// <returns>Returns True on success, or False on failure.</returns>
         [DllImport(Alc.Lib,EntryPoint = "alcMakeContextCurrent",ExactSpelling = true,CallingConvention = Alc.Style),SuppressUnmanagedCodeSecurity( )]
+        [return: MarshalAs(UnmanagedType.I1)]
         public static extern bool MakeContextCurrent( [In] IntPtr context );
         // ALC_API ALCboolean      ALC_APIENTRY alcMakeContextCurrent( ALCcontext *context );