sha512_256_final
ATTRIBUTE_WARN_UNUSED_RET int sha512_256_final(sha512_256_context *ctx, u8 output[SHA512_256_DIGEST_SIZE]);
return sha512_256_final((sha512_256_context*)hctx, output);
ret = sha512_256_final(&ctx, output);
ret = sha512_256_final(&ctx, output);