Найти описание прототипов функций - C#

[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
static extern bool GlobalMemoryStatusEx( [In,Out] MEMORYSTATUSEX lpBuffer);
 
       /// <summary>
    /// contains information about the current state of both physical and virtual memory, including extended memory
    /// </summary>
    [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
    public class MEMORYSTATUSEX
    {
        /// <summary>
        /// Size of the structure, in bytes. You must set this member before calling GlobalMemoryStatusEx. 
        /// </summary>
        public uint dwLength;
 
        /// <summary>
        /// Number between 0 and 100 that specifies the approximate percentage of physical memory that is in use (0 indicates no memory use and 100 indicates full memory use). 
        /// </summary>
        public uint dwMemoryLoad;
 
        /// <summary>
        /// Total size of physical memory, in bytes.
        /// </summary>
        public ulong ullTotalPhys;
 
        /// <summary>
        /// Size of physical memory available, in bytes. 
        /// </summary>
        public ulong ullAvailPhys;
 
        /// <summary>
        /// Size of the committed memory limit, in bytes. This is physical memory plus the size of the page file, minus a small overhead. 
        /// </summary>
        public ulong ullTotalPageFile;
 
        /// <summary>
        /// Size of available memory to commit, in bytes. The limit is ullTotalPageFile. 
        /// </summary>
        public ulong ullAvailPageFile;
 
        /// <summary>
        /// Total size of the user mode portion of the virtual address space of the calling process, in bytes. 
        /// </summary>
        public ulong ullTotalVirtual;
 
        /// <summary>
        /// Size of unreserved and uncommitted memory in the user mode portion of the virtual address space of the calling process, in bytes. 
        /// </summary>
        public ulong ullAvailVirtual;
 
        /// <summary>
        /// Size of unreserved and uncommitted memory in the extended portion of the virtual address space of the calling process, in bytes. 
        /// </summary>
        public ulong ullAvailExtendedVirtual;
 
        /// <summary>
        /// Initializes a new instance of the <see cref="T:MEMORYSTATUSEX"/> class.
        /// </summary>
        public MEMORYSTATUSEX()
        {
           this.dwLength = (uint)Marshal.SizeOf(typeof(NativeMethods.MEMORYSTATUSEX));
        }
       }