c# get system file cache size

Question

I'm trying to get the current system file cache size as shown below. However when I run this code nothing gets returned, can anybody see where I'm going wrong ? FYI the link is GetSystemFileCache.

    [DllImport("kernel32", SetLastError = true, CharSet = CharSet.Unicode)]
    public static extern bool GetSystemFileCacheSize(
        ref IntPtr lpMinimumFileCacheSize,
        ref IntPtr lpMaximumFileCacheSize,
        ref IntPtr lpFlags
        );

    static void Main(string[] args)
    {            
        IntPtr lpMinimumFileCacheSize = IntPtr.Zero;
        IntPtr lpMaximumFileCacheSize = IntPtr.Zero;
        IntPtr lpFlags = IntPtr.Zero;

        bool b = GetSystemFileCacheSize(ref lpMinimumFileCacheSize, ref lpMaximumFileCacheSize, ref lpFlags);
    }

Answer 1

        bool b = GetSystemFileCacheSize(ref lpMinimumFileCacheSize, ref lpMaximumFileCacheSize, ref lpFlags);

        Console.WriteLine(lpMinimumFileCacheSize);
        Console.WriteLine(lpMaximumFileCacheSize);

Works fine for me.

Output:

1048576
2143289344

Windows 7 Pro x32

Answer 2

This code snippet works: (Windows Seven x86)