Returns the new CLSID to which the specified object can be automatically converted. This conversion CLSID is stored in the registration database.

HRESULT OleGetAutoConvert(

REFCLSID clsidOld,
//CLSID of the object to be converted
//Pointer to new CLSID for object being converted



Specifies the CLSID for an object that can be automatically converted.


Points to location where the new CLSID, if any, is returned. The original object, clsidOld, is automatically converted to this new CLSID when the object is opened. If there is no auto-conversion CLSID stored in the registration database, the value clsidOld is returned; the pClsidNew parameter cannot be NULL.

Return Values


Indicates that a value was successfully returned through the pclsidNew parameter.


Indicates the clsidOld CLSID is not properly registered in the registration database.


Indicates error reading the registration database.


Indicates auto convert is not active or there was no registration entry for the clsidOld parameter.


Indicates the value was not returned due to a lack of memory.


Indicates one or more arguments are invalid.


Indicates an unexpected error occurred.


This function returns the AutoConvertTo entry in the registration database for the specified object, which specifies whether objects of a given CLSID are to be automatically converted to a new CLSID. This is usually set up to convert files created by older versions of an application to the current version. If there is no AutoConvertTo entry, this function returns the value of clsidOld. This function is typically called by the OleDoAutoConvert function to determine if the object specified needs to be converted. If the object has an AutoConvertTo entry, then it will be converted.

Automatic conversion is typically set up during the installation of an object application. The setup program can take advantage of the AutoConvertTo subkey to tag a class of objects for automatic conversion to a different class of objects.

For example, a new version of a spreadsheet application may need to convert spreadsheets that were created with earlier versions of the application. These earlier version spreadsheet objects have a different CLSID than the new version. The setup program for the new version of the spreadsheet application tags objects in the registration database that have the old CLSID so they are automatically updated when they are loaded.

To tag the old spreadsheet objects, the setup program calls the OleSetAutoConvert function and passes it to the CLSIDs of the source and destination object classes. The OleSetAutoConvert function creates the required entry in the registration database. These entries appear in the registration database as subkeys of the CLSID key:

CLSID\{clsid}=MainUserTypeName\AutoConvertTo = clsid

See Also

OleSetAutoConvert, OleDoAutoConvert

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