struct PK_BCURVE_join_o_s { int o_t_version; --- version of options structure (1) int n_knots; --- number of knot values (0) double *knots; --- acceptable values to snap to (NULL) double snap_tolerance; --- tolerance for snapping to knots (0.0) }; typedef struct PK_BCURVE_join_o_s PK_BCURVE_join_o_t; Holds optional controls on the joining of bcurves. The option structure defines options applicable to the joining of bcurves.