C++零碎知識

__uuidof Operator

Retrieves the GUID attached to the expression.

__uuidof ( 
   expression  
)

The expression can be a type name, pointer, reference, or array of that type, a template specialized on these types, or a variable of these types. The argument is valid as long as the compiler can use it to find the attached GUID.

A special case of this intrinsic is when either 0 or NULL is supplied as the argument. In this case, __uuidof will return a GUID made up of zeros.

In a debug build, __uuidof always initializes an object dynamically (at runtime). In a release build, __uuidof can statically (at compile time) initialize an object.

摘自http://msdn.microsoft.com/en-us/library/zaah6a61.aspx

SAFEARRAY

Thread Safety

All public static members of the SAFEARRAY data type are thread safe. Instance members are not guaranteed to be thread safe.

摘自http://msdn.microsoft.com/en-us/library/windows/desktop/ms221482(v=vs.85).aspx

http://msdn.microsoft.com/en-us/library/windows/desktop/ms221620(v=vs.85).aspx

ISequentialStream

ISequentialStream is the preferred minimal interface for reading and writing binary large object (BLOB) data in OLE DB. ISequentialStream is a subset of the COM IStream interface and provides forward-only reading and writing of data. The IStream interface inherits its Read and Write methods from ISequentialStream.

摘自http://msdn.microsoft.com/en-us/library/windows/desktop/ms718035(v=vs.85).aspx

CBulkRowset Class

Fetches and manipulates rows to work on data in bulk by retrieving multiple row handles with a single call

摘自http://msdn.microsoft.com/en-us/library/3b0wza3z.aspx

CDynamicAccessor Class

Allows you to access a data source when you have no knowledge of the database schema (the database's underlying structure).

摘自http://msdn.microsoft.com/en-us/library/z828c118.aspx

COleVariant Class

Encapsulates the VARIANT data type.

摘自http://msdn.microsoft.com/en-us/library/4xd0wkhw.aspx