Function svn_fs_revision_root 

pub unsafe extern "C" fn svn_fs_revision_root(
    root_p: *mut *mut svn_fs_root_t,
    fs: *mut svn_fs_t,
    rev: svn_revnum_t,
    pool: *mut apr_pool_t,
) -> *mut svn_error_t

Set @a *root_p to the root directory of revision @a rev in filesystem @a fs. Allocate @a *root_p in a private subpool of @a pool; the root can be destroyed earlier than @a pool by calling #svn_fs_close_root.