how-to-read-windows-performance-counters-cpp-cli.md

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How to: Read Windows Performance Counters (C++/CLI) | Microsoft Docs		11/04/2016			cpp-windows		article	C++	performance counters performance counters, reading Windows performance counters performance monitoring, Windows performance counters performance, counters counters, reading Windows performance counters performance performance monitoring	9e1c836c-cb0f-4f37-9a93-3dca6412d6b1	12	mikeblome	mblome	ghogen

How to: Read Windows Performance Counters (C++/CLI)

Some applications and Windows subsystems expose performance data through the Windows performance system. These counters can be accessed using the xref:System.Diagnostics.PerformanceCounterCategory and xref:System.Diagnostics.PerformanceCounter classes, which reside in the xref:System.Diagnostics?displayProperty=fullName namespace.

The following code example uses these classes to retrieve and display a counter that is updated by Windows to indicate the percentage of time that the processor is busy.

Note

This example requires administrative privileges to run on Windows Vista.

Example

// processor_timer.cpp  
// compile with: /clr  
#using <system.dll>  
  
using namespace System;  
using namespace System::Threading;  
using namespace System::Diagnostics;  
using namespace System::Timers;  
  
ref struct TimerObject  
{  
public:  
   static String^ m_instanceName;  
   static PerformanceCounter^ m_theCounter;  
  
public:  
   static void OnTimer(Object^ source, ElapsedEventArgs^ e)  
   {  
      try   
      {  
         Console::WriteLine("CPU time used: {0,6} ",  
          m_theCounter->NextValue( ).ToString("f"));  
      }   
      catch(Exception^ e)  
      {  
         if (dynamic_cast<InvalidOperationException^>(e))  
         {  
            Console::WriteLine("Instance '{0}' does not exist",  
                  m_instanceName);  
            return;  
         }  
         else  
         {  
            Console::WriteLine("Unknown exception... ('q' to quit)");  
            return;  
         }  
      }  
   }  
};  
  
int main()  
{  
   String^ objectName = "Processor";  
   String^ counterName = "% Processor Time";  
   String^ instanceName = "_Total";  
  
   try  
   {  
      if ( !PerformanceCounterCategory::Exists(objectName) )  
      {  
         Console::WriteLine("Object {0} does not exist", objectName);  
         return -1;  
      }  
   }  
   catch (UnauthorizedAccessException ^ex)  
   {  
      Console::WriteLine("You are not authorized to access this information.");  
      Console::Write("If you are using Windows Vista, run the application with ");  
      Console::WriteLine("administrative privileges.");  
      Console::WriteLine(ex->Message);  
      return -1;  
   }  
  
   if ( !PerformanceCounterCategory::CounterExists(  
          counterName, objectName) )  
   {  
      Console::WriteLine("Counter {0} does not exist", counterName);  
      return -1;  
   }  
  
   TimerObject::m_instanceName = instanceName;  
   TimerObject::m_theCounter = gcnew PerformanceCounter(  
          objectName, counterName, instanceName);  
  
   System::Timers::Timer^ aTimer = gcnew System::Timers::Timer();  
   aTimer->Elapsed += gcnew ElapsedEventHandler(&TimerObject::OnTimer);  
   aTimer->Interval = 1000;  
   aTimer->Enabled = true;  
   aTimer->AutoReset = true;  
  
   Console::WriteLine("reporting CPU usage for the next 10 seconds");  
   Thread::Sleep(10000);  
   return 0;  
}  

See Also

Introduction to Monitoring Performance
Windows Operations (C++/CLI)
.NET Programming with C++/CLI (Visual C++)