netcore/System.Private.CoreLib/shared/System/Diagnostics/Stopwatch.Windows.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 namespace System.Diagnostics
   6 {
   7     public partial class Stopwatch
   8     {
   9         private static unsafe long QueryPerformanceFrequency()
  10         {
  11             long resolution;
  12
  13             Interop.BOOL result = Interop.Kernel32.QueryPerformanceFrequency(&resolution);
  14             // The P/Invoke is documented to never fail on Windows XP or later
  15             Debug.Assert(result != Interop.BOOL.FALSE);
  16
  17             return resolution;
  18         }
  19
  20         private static unsafe long QueryPerformanceCounter()
  21         {
  22             long timestamp;
  23
  24             Interop.BOOL result = Interop.Kernel32.QueryPerformanceCounter(&timestamp);
  25             // The P/Invoke is documented to never fail on Windows XP or later
  26             Debug.Assert(result != Interop.BOOL.FALSE);
  27
  28             return timestamp;
  29         }
  30     }
  31 }