Function svn_fs_node_id 

pub unsafe extern "C" fn svn_fs_node_id(
    id_p: *mut *const svn_fs_id_t,
    root: *mut svn_fs_root_t,
    path: *const c_char,
    pool: *mut apr_pool_t,
) -> *mut svn_error_t

Get the id of a node.

Set @a *id_p to the node revision ID of @a path in @a root, allocated in @a pool.

If @a root is the root of a transaction, keep in mind that other changes to the transaction can change which node @a path refers to, and even whether the path exists at all.