\param cn CQL node (tree)
\param out buffer
\param max size of buffer (max chars to write)
- \returns length of resulting buffer
+ \retval 0 OK
+ \retval -1 conversion error
+ \retval -2 buffer too small (truncated)
*/
YAZ_EXPORT
int cql_to_ccl_buf(struct cql_node *cn, char *out, int max);