#define CvROOT(sv)      ((XPVCV*)SvANY(sv))->xcv_root_u.xcv_root
#define CvXSUB(sv)      ((XPVCV*)SvANY(sv))->xcv_root_u.xcv_xsub
 
#define CvOUTSIDE(sv)   ((XPVCV*)SvANY(sv))->xcv_outside