* @EC_EXPLY@ is set, then an explicit %$y$%-coordinate is
* output in full. Otherwise the %$y$%-coordinate is
* suppressed.
+ *
+ * Returns failure (@-1@) if the flags are invalid, or if there
+ * isn't enough space in the output buffer.
*/
extern int ec_ec2osp(ec_curve */*c*/, unsigned /*f*/,