XXX_Init

typedef struct XXX_Init_tag {
  char  version[8];        /* to check correct XXX version */

  /*** used internally by xxx_init(), xxx_do(), and xxx_end() */
  INT_PTR interna[4];     /* do not change */
} XXX_Init;

Elements:

version[8]
Check of the correct ✘✘✘ Signature version.
interna[4]
Do not change.

Reference: