>The SID structure is a variable-length structure used to uniquely identify users or groups. SID stands for security identifier.
>Applications are not to modify the SID structure directly. To create and manipulate a security identifier, use the functions listed in the See Also section.
>typedef PVOID PSID;
>
>See Also
>AllocateAndInitializeSid, CopySid, EqualSid, FreeSid, GetLengthSid, GetSidIdentifierAuthority, GetSidLengthRequired, GetSidSubAuthority, GetSidSubAuthorityCount, InitializeSid, IsValidSid, LookupAccountName, LookupAccountSid

Thanks, but do you think I need to deal with SID if I only want to apply trustee s on a directory using SetFileSecurity()?