The OpenVMS LDAP library uses 64-bit pointers internally and is
    capable of dealing with data structures allocated by the caller
    from 64-bit address space.

    Applications that use 32-bit pointers will use the 32-bit
    function entry points in the library. This means they can pass
    arguments that are based on 32-bit pointers and can assume that
    any pointers returned by the library will be 32-bit safe.

    While the mapping performed by LDAP.H is designed to be
    transparent, there may be occasions where it is useful (for
    example in debugging) to understand the consequences of having
    both 32- and 64-bit support in the same library.