DynData v1.01

Welcome to DynData, A collection of freeware MFC classes to encapsulate the performance counters as stored under the HKEY_DYN_DATA registry key on Windows 9x. Please note that these classes are not designed to be used on NT, 2000, XP, 2003, Vista. If you would like to retrieve performance stats on these operating systems, please see the author's CPdh wrapper classes.

Features

• Simple and clean C++ interface based.
• The classes are fully Unicode compliant (even though HKEY_DYN_DATA is not available on NT <g>)
• Full documentation is provided in the form of a HTML file (This file!).

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.

Usage

• To use the classes in your code, just include "dyndata.h" in which ever module requires it and also include the dyndata cpp and h file in your project.
• Please note that these classes are not designed to be used on NT, 2000, XP, 2003, Vista, since these operating systems provide their own kind of performance data using a different retrieval mechanism. If you would like to retrieve performance stats on these operating systems, please see the author's CPdh wrapper classes.,
• You will need an up to date Platform SDK installed to compile the code if you are using Visual C++ 6 (February 2003 was the last version which was compatible with VC 6).

History

V1.0 (31 January 1999)

• First public release.

V1.01 (10 January 2007)

• Updated copyright details.
• Addition of a DYNDATA_EXT_CLASS preprocessor macro to allow the classes to be more easily added to an extension dll
• Optimized CDynDataObject constructor code.
• Reviewed all TRACE statements for correctness
• Code now uses newer C++ style casts instead of C style casts.
• Item data value passed to the various enumeration functions is now a DWORD_PTR instead of a DWORD
• ENUMERATE_DYNDATA_OBJECT_COUNTERS is now declared in the CDynDataObject class scope
• ENUMERATE_DYNDATA_OBJECTS is now declared in the CDynDataEnumerator class scope
• Updated the code to clean compile on VC 2005
• Fixed a bug in the calculation of the buffer sizes passed to RegQueryValueEx in CDynDataObject::_EnumCounters
• General code cleanup and code review
• Updated documentation to use the same style as the web site

API Reference

The DynData classes provide the following functions:

CDynDataObject::CDynDataObject
CDynDataObject::EnumCounters
CDynDataEnumerator::EnumObjects
CDynDataCounter::Start
CDynDataCounter::Collect
CDynDataCounter::Stop
 

CDynDataObject::CDynDataObject

CDynDataObject::CDynDataObject(LPCTSTR pszObjName, HKEY hObjectKey);
CDynDataObject::CDynDataObject(LPCTSTR pszObjName, LPCTSTR pszComputerName);

Parameters

pszObjName This is the name of the performance object e.g. "Dial-Up Adapter" or "Kernel".

hObjectKey This is the registry key which represents the performance object.

pszComputerName This is the name of the computer on which to open the performance object. Set this value to NULL to open the object on the local machine.

Remarks

Constructs a performance object which can be later used for enumeration. The first version of the constructor is used internally by the CDynDataEnumerator class. Normally to enumerate the counters which an object has you would use the second version. Another point to bear in mind is that since the two constructors look pretty much identical, you will need to cast the NULL to a LPCTSTR if you are calling the second constructor yourself.

CDynDataObject::EnumCounters

BOOL CDynDataObject::EnumCounters(ENUMERATE_DYNDATA_OBJECT_COUNTERS lpEnumFunc, DWORD_PTR dwItemData = 0);

Parameters

lpEnumFunc The function to be used as the call-back when enumerating the counters which this object has.

dwItemData This is a DWORD_PTR which can be anything you want and will be sent to the call-back function.

Return Value

TRUE if at least one counter was successfully enumerated for the performance object otherwise FALSE.

Remarks

The call-back function is of the form:

typedef BOOL (*ENUMERATE_DYNDATA_OBJECT_COUNTERS)(DWORD_PTR dwItemData, CDynDataObject& object, const CString& sRegistryName, const CString& sCommonName, const CString& sDescription, BOOL bDifferentiate);

The dwItemData is the value as presented in the EnumCounters function.

The object parameter represents the performance object being enumerated.

The sRegistryName is the name of the counter as stored in the registry.

The sCommonName is the name of the counter which you would display to an end user.

The sDescription is a description of the counter.

If bDifferentiate is TRUE, then the counter represents a rate such as Bytes Received per Second as opposed to an absolute value such as bytes sent.

Returning TRUE from the call-back function will continue the enumeration while returning FALSE will cause the enumeration to stop.

CDynDataEnumerator::EnumObjects

BOOL CDynDataEnumerator::EnumObjects(ENUMERATE_DYNDATA_OBJECTS lpEnumFunc, DWORD_PTR dwItemData = 0,  LPCTSTR pszComputerName = NULL);

Parameters

lpEnumFunc The function to be used as the call-back when enumerating the performance objects.

dwItemData This is the value as presented in the EnumObjects function.

pszComputerName This is the name of the computer of which to enumerate the performance objects. Set this value to NULL to enumerate the objects on the local machine.

Return Value

TRUE if at least one object was successfully enumerated otherwise FALSE.

Remarks

The call-back function is of the form:

typedef BOOL (*ENUMERATE_DYNDATA_OBJECTS)(DWORD_PTR dwItemData, CDynDataObject& object);

The dwItemData is the value as in the EnumObjects function.

The object parameter represents the current performance object being enumerated.

Returning TRUE from the call-back function will continue the enumeration while returning FALSE will cause the enumeration to stop.

CDynDataCounter::Start

BOOL CDynDataCounter::Start(LPCTSTR pszObjName pszObjName, LPCTSTR pszCounterName,  LPCTSTR pszComputerName = NULL);

Parameters

pszObjName The name of the performance object e.g. "KERNEL".

pszCounterName The name of the counter for the performance object e.g. "CPUUsage".

pszComputerName This is the name of the computer on which the counter is to be collected.  Set this value to NULL to start collection on the local machine.

Return Value

TRUE if collection of the performance data was started otherwise FALSE.

Remarks

Starts collection of the performance data.

CDynDataCounter::Collect

BOOL CDynDataCounter::Collect(DWORD& dwData);

Parameters

dwData Upon successful return of the function this will contain the actual value of the performance counter.

Return Value

TRUE if collection of the performance data was successful otherwise FALSE.

Remarks

Retrieves the current value of the performance counter.

CDynDataCounter::Stop

BOOL CDynDataCounter::Stop();

Return Value

TRUE if collection of the performance data was successfully stopped otherwise FALSE.

Remarks

Stops retrieval of the performance counter.

Contacting the Author

PJ Naughter
Email: pjna@naughter.com
Web: http://www.naughter.com
10 January 2007