WJUMP2
# define WJUMP2(FUNC, THIS, X1, X2) _IO_WIDE_JUMPS_FUNC(THIS)->FUNC.pfn (THIS, X1, X2)
#define WJUMP2(FUNC, THIS, X1, X2) (_IO_WIDE_JUMPS_FUNC(THIS)->FUNC) (THIS, X1, X2)