These functions create and destroy struct missing_values objects.
void mv_init (struct missing_values *mv, int width) ¶Initializes mv as a set of user-missing values. The set is initially empty. Any values added to it must have the specified width.
void mv_destroy (struct missing_values *mv) ¶Destroys mv, which must not be referred to again.
void mv_copy (struct missing_values *mv, const struct missing_values *old) ¶Initializes mv as a copy of the existing set of user-missing values old.
void mv_clear (struct missing_values *mv) ¶Empties the user-missing value set mv, retaining its existing width.