ILRUCache::Lookup Method [C++]

Article
11/12/2009

Use this method to retrieve the value of an element from the cache.

Definition

[C++]

HRESULT ILRUCache::Lookup(BSTRbstrKey,
  VARIANT*pvarValue);

[Visual Basic]

Function Lookup(bstrKey As String) As Variant

Parameters

bstrKey[C++]
[in] A BSTR that contains the name of the element to be retrieved.
bstrKey[Visual Basic]
A String that contains the name of the element to be retrieved.
pvarValue[C++]
[out,retval] A pointer to a VARIANT used to return the value.

Return Values

[C++] This method returns an HRESULT indicating whether it completed successfully. See the Error Values section for more details.

[Visual Basic] If this method completes successfully, it returns a Variant that contains the value of the specified element.

Error Values

[C++] This method returns S_OK (0x00000000) to indicate success and standard COM HRESULT error values to indicate failure. For more information about standard COM errors, see Standard COM Errors. Additional information may be available using the global Err object, which can be accessed using the API function GetErrorInfo. In particular, the GetDescription method of the IErrorInfo interface may return a text description of the error.

[Visual Basic] This method sets the Number property of the global Err object to S_OK (&H00000000) to indicate success and to standard COM error values to indicate failure. For more information about standard COM errors, see Standard COM Errors. Additional information may be available using the global Err object. In particular, the Description property may contain a text description of the error.

Remarks

[C++] The pvarValue parameter contains valid data only if the property was accessed successfully.

For more information about memory ownership issues related to COM property and method parameters, see Managing COM Parameter Memory.