netcore/System.Private.CoreLib/shared/Interop/Windows/Kernel32/Interop.GetComputerName.cs

   1 // Licensed to the .NET Foundation under one or more agreements.
   2 // The .NET Foundation licenses this file to you under the MIT license.
   3 // See the LICENSE file in the project root for more information.
   4
   5 #nullable enable
   6 using System;
   7 using System.Runtime.InteropServices;
   8
   9 internal static partial class Interop
  10 {
  11     internal static partial class Kernel32
  12     {
  13         [DllImport(Libraries.Kernel32, CharSet = CharSet.Unicode, EntryPoint = "GetComputerNameW")]
  14         private static extern unsafe int GetComputerName(ref char lpBuffer, ref uint nSize);
  15
  16         // maximum length of the NETBIOS name (not including NULL)
  17         private const int MAX_COMPUTERNAME_LENGTH = 15;
  18
  19         internal static unsafe string? GetComputerName()
  20         {
  21             Span<char> buffer = stackalloc char[MAX_COMPUTERNAME_LENGTH + 1];
  22             uint length = (uint)buffer.Length;
  23
  24             return GetComputerName(ref MemoryMarshal.GetReference(buffer), ref length) != 0 ?
  25                 buffer.Slice(0, (int)length).ToString() :
  26                 null;
  27         }
  28     }
  29 }