sk_value
((type *)sk_value(CHECKED_STACK_OF(type, st), i))
#define sk_OPENSSL_STRING_value(st, i) ((OPENSSL_STRING)sk_value(CHECKED_STACK_OF(OPENSSL_STRING, st), i))
#define sk_OPENSSL_BLOCK_value(st, i) ((OPENSSL_BLOCK)sk_value(CHECKED_STACK_OF(OPENSSL_BLOCK, st), i))
#define sk_OPENSSL_PSTRING_value(st, i) ((OPENSSL_PSTRING)sk_value(CHECKED_STACK_OF(OPENSSL_PSTRING, st), i))
void *sk_value(const _STACK *, int);