This structure contains an array of entities of type PK_VERTEX_t


typedef struct PK_VERTEX_array_s
    {
    PK_VERTEX_t    *array;   --- array of VERTEXs
    int             length;  --- length of array
    }
    PK_VERTEX_array_t;

It has the fields:

array:   array of entities of type PK_VERTEX_t

length:  the number of entities in array