NetAccessGetUserPerms or Net32AccessGetUserPerms

The NetAccessGetUserPerms API supplies a specified user's or group's permission to a resource. The resource can be a file, directory, drive, or logical resource and can be specified remotely by a universal naming convention (UNC) path as well as by a server name.

The permissions returned are based on the user's entry and the entry for any groups to which the user belongs. Priority always is given to the user's entry, if one exists.