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2.3.4 Inspecting User-Missing Value Sets

These functions inspect the properties and contents of struct missing_values objects.

The first set of functions inspects the discrete values that numeric and short string sets of user-missing values may contain:

— Function: bool mv_is_empty (const struct missing_values *mv)

Returns true if mv contains no user-missing values, false if it contains at least one user-missing value (either a discrete value or a numeric range).

— Function: int mv_get_width (const struct missing_values *mv)

Returns the width of the user-missing values that mv represents.

— Function: int mv_n_values (const struct missing_values *mv)

Returns the number of discrete user-missing values included in mv. The return value will be between 0 and 3. For sets of numeric user-missing values that include a range, the return value will be 0 or 1.

— Function: bool mv_has_value (const struct missing_values *mv)

Returns true if mv has at least one discrete user-missing values, that is, if mv_n_values would return nonzero for mv.

— Function: void mv_get_value (const struct missing_values *mv, union value *value, int index)

Copies the discrete user-missing value in mv with the given index into value. The index must be less than the number of discrete user-missing values in mv, as reported by mv_n_values.

The second set of functions inspects the single range of values that numeric sets of user-missing values may contain:

— Function: bool mv_has_range (const struct missing_values *mv)

Returns true if mv includes a range, false otherwise.

— Function: void mv_get_range (const struct missing_values *mv, double *low, double *high)

Stores the low endpoint of mv's range in *low and the high endpoint of the range in *high. mv must include a range.