PutClassAsync method

IWbemServices::PutClassAsync method

The IWbemServices::PutClassAsync method creates a new class, or updates an existing one. The class specified by the pObject parameter must be correctly initialized with all of the required property values. The call immediately returns. Success or failure is supplied to the object sink specified by the pResponseHandler parameter.


HRESULT PutClassAsync(
  [in] IWbemClassObject *pObject,
  [in] LONG             lFlags,
  [in] IWbemContext     *pCtx,
  [in] IWbemObjectSink  *pResponseHandler


pObject [in]

Pointer to the object containing the class definition.

lFlags [in]

One or more of the following values are valid.


If this flag is set, WMI does not store any qualifiers with the amended flavor. If this flag is not set, it is assumed that this object is not localized, and all qualifiers are stored with this instance.


This flag causes this class to be created if it does not exist or be overwritten if it exists already.


Updates an existing class.


This flag is for class creation only. The call fails if the class already exists.


This flag registers with Windows Management a request to receive intermediate status reports through the client's implementation of IWbemObjectSink::SetStatus. Provider implementation must support intermediate status reporting for this flag to change behavior.


Push providers must specify this flag when calling PutClassAsync to indicate that this class has changed.


This flag allows a class to be updated if there are no derived classes and there are no instances for that class. It also allows updates in all cases if the change is just to non-important qualifiers (for example, the Description qualifier). This is the default behavior for this call and is used for compatibility with previous versions of Windows Management. If the class has instances or changes are to important qualifiers, the update fails.


This flag allows updates of classes even if there are child classes, as long as the change does not cause any conflicts with child classes. An example of an update this flag would allow would be to add a new property to the base class that was not previously mentioned in any of the child classes. If the class has instances, the update fails.


This flag forces updates of classes when conflicting child classes exist. An example of an update this flag would force would be if a class qualifier were defined in a child class, and the base class tried to add the same qualifier which conflicted with the existing one. In force mode, this conflict would be resolved by deleting the conflicting qualifier in the child class.


pCtx [in]

Typically NULL. Otherwise, this is a pointer to an IWbemContext object that may be used by the provider that is receiving the requested class. The values in the context object must be specified in the documentation for the provider in question. For more information about this parameter, see Making Calls to WMI.

pResponseHandler [in]

Pointer to the caller's implementation of IWbemObjectSink. This handler receives the status of the Put request when the status becomes available using the SetStatus method. If any error code is returned, then the supplied IWbemObjectSink pointer is not used. If WBEM_S_NO_ERROR is returned, then the user's IWbemObjectSink implementation is called to indicate the result of the operation. Windows Management only calls AddRef to the pointer in cases where WBEM_S_NO_ERROR returns. In cases where an error code returns, the reference count is the same as on entry. For a detailed explanation of this parameter, see Calling a Method.

Return value

This method returns an HRESULT indicating the status of the method call. The following table lists the value contained within an HRESULT.

Other status or error codes are reported to the object sink specified by the pReponseHandler parameter.

COM-specific error codes also may be returned if network problems cause you to lose the remote connection to Windows Management.

Note that if PutInstanceAsync returns WBEM_S_NO_ERROR, WMI waits for a result from the SetStatus method of the response handler. WMI waits indefinitely on a local connection or until a remote connection time-out occurs.

Because returning WBEM_E_FAILED causes other providers to not have a chance to create the class, it should only be returned when the class provider has failed in a way that might later succeed.

Note  Unpredictable behavior will result if you change class definitions while they are in use by clients or providers. The IWbemServices::PutClass method should only be used to create or update a class when there are no clients or providers currently using the class.
Return codeDescription

The current user does not have permission to create classes.


WBEM_FLAG_CREATE_ONLY flag was specified, but the class already exists.


This is an unspecified failure.


The class specified is not valid. You will see this error if a instance object is specified in the pObject parameter.


The class name specified is not valid.


An attempt was made to make a change that would invalidate a subclass.


The required properties for classes have not all been set.


A specified parameter is not valid.


WBEM_FLAG_UPDATE_ONLY flag was specified, but the class does not exist.


There was not enough memory to complete the operation.


This indicates the failure of the remote procedure call (RPC) link between the current process and Windows Management.


The call succeeded.


The provider could not recognize the class name.


The provider cannot create or update classes. Return this error code in all cases if a more specific code is not required.


Windows Management service was probably stopped and restarted. A new call to ConnectServer is needed.



If multiple class providers are installed for one particular class, WMI will not recognize which class provider is capable of creating that class.

The IWbemObjectSink::SetStatus method is called to indicate the end of the result set. It may also be called with no intervening calls to IWbemObjectSink::Indicate if error conditions occur.

Because the call-back might not be returned at the same authentication level as the client requires, it is recommended that you use semisynchronous instead of asynchronous communication. If you require asynchronous communication, see Calling a Method.

For more information about using methods semisynchronously, see IWbemServices::PutClass and Calling a Method.


The following code example describes a simple implementation of PutClassAsync.

HRESULT CStdProvider::PutClassAsync( 
            /* [in] */ IWbemClassObject __RPC_FAR *pObject,
            /* [in] */ long lFlags,
            /* [in] */ IWbemContext __RPC_FAR *pCtx,
            /* [in] */ IWbemObjectSink __RPC_FAR *pResponseHandler
    // You must implement the ClassIsValid function yourself to
    // determine if the class contains a valid instance
   if (ClassIsValid(lFlags, pObject))
       return WBEM_S_NO_ERROR;



Minimum supported client

Windows Vista

Minimum supported server

Windows Server 2003


Wbemcli.h (include Wbemidl.h)





See also

Creating a Class
Calling a Method



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