OleLoad function (ole2.h)

Article
02/22/2024

Loads into memory an object nested within a specified storage object.

Syntax

HRESULT OleLoad(
  [in]  LPSTORAGE       pStg,
  [in]  REFIID          riid,
  [in]  LPOLECLIENTSITE pClientSite,
  [out] LPVOID          *ppvObj
);

Parameters

[in] pStg

Pointer to the IStorage interface on the storage object from which to load the specified object.

[in] riid

Reference to the identifier of the interface that the caller wants to use to communicate with the object after it is loaded.

[in] pClientSite

Pointer to the IOleClientSite interface on the client site object being loaded.

[out] ppvObj

Address of pointer variable that receives the interface pointer requested in riid. Upon successful return, *ppvObj contains the requested interface pointer on the newly loaded object.

Return value

This function returns S_OK on success. Other possible values include the following.

Return code	Description
E_NOINTERFACE	The object does not support the specified interface.

Additionally, this function can return any of the error values returned by the IPersistStorage::Load method.

Remarks

OLE containers load objects into memory by calling this function. When calling the OleLoad function, the container application passes in a pointer to the open storage object in which the nested object is stored. Typically, the nested object to be loaded is a child storage object to the container's root storage object. Using the OLE information stored with the object, the object handler (usually, the default handler) attempts to load the object. On completion of the OleLoad function, the object is said to be in the loaded state with its object application not running.

Some applications load all of the object's native data. Containers often defer loading the contained objects until required to do so. For example, until an object is scrolled into view and needs to be drawn, it does not need to be loaded.

The OleLoad function performs the following steps:

If necessary, performs an automatic conversion of the object (see the OleDoAutoConvert function).
Gets the CLSID from the open storage object by calling the IStorage::Stat method.
Calls the CoCreateInstance function to create an instance of the handler. If the handler code is not available, the default handler is used (see the OleCreateDefaultHandler function).
Calls the IOleObject::SetClientSite method with the pClientSite parameter to inform the object of its client site.
Calls the QueryInterface method for the IPersistStorage interface. If successful, the IPersistStorage::Load method is invoked for the object.
Queries and returns the interface identified by the riid parameter.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	ole2.h
Library	Ole32.lib
DLL	Ole32.dll