.

public static extern int GetSystemWow64Directory([In, Out] char[] lpBuffer, [MarshalAs(UnmanagedType.U4)] uint size);

.

public static extern int GetSystemWow64Directory([Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder lpBuffer, [MarshalAs(UnmanagedType.U4)] uint size);

.

Private Declare Function GetSystemWow64Directory Lib "Kernel32.dll" Alias _

.

      "GetSystemWow64DirectoryA" (ByVal lpBuffer As String, ByVal uSize As Long) As Integer

.

    public static extern int GetSystemWow64Directory([In, Out] char[] lpBuffer, [MarshalAs(UnmanagedType.U4)] uint size);

.

    int result = GetSystemWow64Directory(path, (uint)path.Length);

.

    private static extern int GetSystemWow64Directory([Out, MarshalAs(UnmanagedType.LPWStr)] StringBuilder lpBuffer, [MarshalAs(UnmanagedType.U4)] uint size);

.

    if (GetSystemWow64Directory(buffer, (uint)buffer.Capacity) != 0)

.

    Private Declare Function GetSystemWow64Directory Lib "Kernel32.dll" Alias _

.

      "GetSystemWow64DirectoryA" (ByVal lpBuffer As String, ByVal uSize As Integer) As Integer

.

    Dim Result As Integer = GetSystemWow64Directory(DirPath, DirPath.Length)

.

Documentation

[GetSystemWow64Directory] on MSDN http://msdn2.microsoft.com/en-us/library/ms724405(VS.85).aspx