typedef struct pre##_cfbctx { \
pre##_ctx ctx; /* Underlying cipher context */ \
unsigned off; /* Offset into @iv@ buffer */ \
- octet iv[PRE##_BLKSZ]; /* Previous ciphertext or IV */ \
+ octet b[PRE##_BLKSZ]; /* Previous ciphertext or IV */ \
} pre##_cfbctx; \
\
/* --- @pre_cfbgetiv@ --- * \