Storage and stream objects are named according to a set of conventions.
The name of a root storage object is the actual name of the file in the underlying file system. It obeys the conventions and restrictions the file system imposes. Filename strings passed to storage-related methods and functions are passed on, uninterpreted and unchanged, to the file system.
The name of a nested element contained within a storage object is managed by the implementation of the particular storage object. All implementations of storage objects must support nested element names 32 characters in length (including the NULL terminator), although some implementations might support longer names. Whether the storage object does any case conversion is implementation-defined. As a result, applications that define element names must choose names that are acceptable in either situation. The COM implementation of compound files supports names up to 32 characters in length, and does not perform any case conversion.