IWbemServices::ExecNotificationQuery

[This is preliminary documentation and subject to change.]

The IWbemServices::ExecNotificationQuery method executes a query to receive events. The call returns immediately, and the user can poll the returned enumerator for events as they arrive. Releasing the returned enumerator cancels the query.

HRESULT IWbemServices::ExecNotificationQuery(
  [in] BSTR bstrQueryLanguage,             
  [in] BSTR bstrQuery,                     
  [in] LONG lFlags,                    
  [in] IWbemContext *pCtx,              
  [out] IEnumWbemClassObject **ppEnum       
);

Parameters

bstrQueryLanguage
A valid BSTR containing one of the query languages supported by CIMOM. This cannot be NULL. Currently, only the WBEM Query Language (WQL) is supported.
bstrQuery
A valid BSTR containing the text of the event-related query. This cannot be NULL.
lFlags
Reserved. It must be zero.
pCtx
Typically NULL. Otherwise, this is a pointer to an IWbemContext object required by the dynamic class provider that is producing the class instances. The values in the context object must be specified in the documentation for the provider in question.
ppEnum
If no error occurs, this receives the enumerator that allows the caller to retrieve the instances in the result set of the query. The caller periodically calls IEnumWbemClassObject::Next to see if any events are available. Notice that in this usage, Reset does not move the enumerator back to the beginning of the event sequence; it has no effect. The parameter can continue to receive events until Release is called on the returned enumerator.

Return Values

WBEM_E_ACCESS_DENIED The current user is not authorized to view the result set.
WBEM_E_FAILED Other unspecified errors.
WBEM_E_INVALID_PARAMETER An invalid parameter was specified, or the namespace could not be parsed.
WBEM_E_INVALID_QUERY The query was not syntactically valid.
WBEM_E_INVALID_QUERY_LANGUAGE The requested query language is not supported.
WBEM_E_OUT_OF_MEMORY There was not enough memory to complete the operation.
WBEM_E_TRANSPORT_FAILURE The communications link between the client and CIMOM has failed.
WBEM_NO_ERROR The call succeeded.

On failure, you can obtain any available information from the COM function GetErrorInfo.

See Also

Error Objects, IWbemServices::ExecNotificationQueryAsync, Queries