CPdh v1.11 A collection of MFC classes to encapsulate the NT Performance Counters

Ever wanted to write some code to determine the amount of bytes sent or received by Dial-Up Networking, what is the current CPU Usage or how many threads are currently running on the system?. The classes provided allow you do query any of these parameters, or to query the availability of performance objects and their counters both on the local machine and any machine on the network. Please note that since Windows 9x has its own version of performance counters which are incompatible with the NT versions, these classes will not work on Windows 9x. If you want classes to work with Windows 9x, have a look at the DynData classes which I have developed. If you do not have the PDH dll on your machine, then you can download it here.

Please note that some users have reported an access violation in advapi.dll when using performance counters on pre SP2 Windows 2000 machines. This is not a bug in my classes but a bug in Windows. For more information please see the MS KB article http://support.microsoft.com/default.aspx?scid=kb;en-us;Q264629&gssnb=1

Features

• Simple and clean C++ interface based.
• The classes are fully Unicode compliant.
• Full documentation is provided in the form of a HTML file

The enclosed zip file contains the source code and a simple console based application which exercises the class.

Copyright

• You are allowed to include the source code in any product (commercial, shareware, freeware or otherwise) when your product is released in binary form.
• You are allowed to modify the source code in any way you want except you cannot modify the copyright details at the top of each module.
• If you want to distribute source code with your application, then you are only allowed to distribute versions released by the author. This is to maintain a single distribution point for the source code.

Updates

V1.0 (9 February 1999)

• Initial Release.

V1.01 (5 September 1999)

• Fixed a bug in pjPdhState::pjPdhState in CPDHIMPL.CPP which was causing an access violation

V1.02 (13 September 1999)

• Fixed a problem which was causing an unhandled exception being thrown when the PDH.DLL is not present on client machines.

V1.03 (25 January 2000)

• Minor update to improve the trace statements when exceptions are thrown.

V1.04 (24 March 2000)

• Fixed a problem with size of arrays in CPdh::EnumMachines, CPdh::EnumObjects, CPdh::EnumObjectItems, CPdh::GetDefaultCounter, CPdh::GetDefaultObject and CPdh::ParseInstanceName when compiled for UNICODE.

V1.05 (14 April 2001)

• Fixed a compile problem when statically linking to MFC.
• Updated copyright information.
• Fixed a bug when calling PdhMakeCounterPath which was causing corruption.
• Fixed a memory leak in CPdhCounter::CPdhCounter.

V1.06 (26 October 2001)

• Fixed a bug in EnumObjectItems, EnumObjects, EnumMachines and ExpandPath where unitialized data was being parsed. Thanks to Petr Stehlik for spotting the problem.
• Fixed a number of functions where on Windows XP you get returned PDH_MORE_DATA even when just asking for the buffer size to allocate.

V1.07 (15 February 2003)

• Added some diagnostic code to CPDHQuery::Close() to ASSERT if any counters are still present in the query when a query object is being destroyed. Some users of CPdh have reported problems with leaks in some versions of PDH.DLL when on Windows NT 4/SP6 when do call Add() to add a counter to a query, you must call Remove() before deleting either the Query or the counter. Failure to do so give quite a hefty memory leak. The Microsoft docs imply you don't need to do this. Thanks to Pete Williams for reporting this. Please note that this is not a bug in the CPDH classes but in PDH.dll itself (or at least some versions of it.
• Addition of operators in the query and counter class to return the underlying HCOUNTER / HQUERY.

V1.08 (27 December 2006)

• Updated copyright details.
• Updated the documentation to use the same style as the web site.
• Code now uses new C++ style casts rather than old style C casts where necessary.
• Optimized CPdhException constructor code
• Removed CPdhException destructor code as it was not really required
• Optimized CPdhCounter constructor code
• Removed CPdhCounter destructor code as it was not really required
• Optimized CPdhQuery constructor code
• Fix a minor copy and paste bug in CPdh::EnumObjects
• Updated code to clean compile on VC 2005
• CPdhQuery::Add now takes an additional BOOL parameter to specify if PdhAddCounter or PdhAddEnglishCounter should be used
• CPdh::GetDefaultObject now allows the data source to be specified
• CPdh::EnumObjects now allows the data source to be specified
• CPdh::EnumObjectItems now allows the data source to be specified
• CPdhQuery::Open now allows the data source to be specified
• Updated the documentation to provide a more concise description of the various classes and their functionality.
• Added support for the following PDH functions:

  PdhAddEnglishCounter,
  PdhBindInputDataSource,
  PdhBrowseCountersH,
  PdhCloseLog,
  PdhCollectQueryDataEx,
  PdhCollectQueryDataWithTime,
  PdhEnumLogSetNames,
  PdhEnumMachinesH,
  PdhEnumObjectItemsH,
  PdhEnumObjectsH
  PdhExpandCounterPathH,
  PdhExpandWildCardPath
  PdhExpandWildCardPathH,
  PdhFormatFromRawValue,
  PdhGetCounterTimeBase,
  PdhGetDataSourceTimeRange,
  PdhGetDataSourceTimeRangeH,
  PdhGetDefaultPerfCounterH,
  PdhGetDefaultPerfObjectH,
  PdhGetFormattedCounterArray,
  PdhGetLogFileSize,
  PdhIsRealTimeQuery,
  PdhLookupPerfIndexByName,
  PdhLookupPerfNameByIndex,
  PdhOpenLog
  PdhOpenQueryH,
  PdhReadRawLogRecord,
  PdhSelectDataSource,
  PdhSetDefaultRealTimeDataSource,
  PdhSetQueryTimeRange,
  PdhUpdateLog
  PdhValidatePathEx

V1.09 (17 March 2007)

• Updated copyright details.
• Updated the documentation for the code to refer to the need for the Platform SDK if you are compiling on VC 6. Thanks to Nicolas MEURET for reporting this issue.

V1.10 (27 December 2007)

• CPdhException::GetErrorMessage now uses the FORMAT_MESSAGE_IGNORE_INSERTS flag. For more information please see Raymond Chen's blog at http://blogs.msdn.com/oldnewthing/archive/2007/11/28/6564257.aspx. Thanks to Alexey Kuznetsov for reporting this issue.
• Minor update to display HRESULT's correctly in CPdh::ThrowPdhException
• CPDHException::GetErrorMessage now uses Checked::tcsncpy_s if compiled using VC 2005 or later.

V1.11 (12 January 2008)

• Updated copyright details.
• Updated the code and sample app to clean compile on VC 2008
• CPdhException::GetErrorMessage now only calls the FormatMessage function once. The second call is not required following a review of the FormatMessage documentation.
• CPdhException::GetErrorMessage now uses the correct return value from FormatMessage.