struct xpvhv {
    char *  xhv_array;  /* pointer to malloced string */
    STRLEN  xhv_fill;   /* how full xhv_array currently is */
    STRLEN  xhv_max;    /* subscript of last element of xhv_array */
    IV      xhv_keys;   /* how many elements in the array */
    NV      xnv_nv;     /* numeric value, if any */
#define xhv_placeholders xnv_nv
    MAGIC*  xmg_magic;  /* magic for scalar array */
    HV*     xmg_stash;  /* class package */

    I32     xhv_riter;  /* current root of iterator */
    HE      *xhv_eiter; /* current entry of iterator */
    PMOP    *xhv_pmroot;    /* list of pm's for this package */
    char    *xhv_name;  /* name, if a symbol table */
};