C++ 用c++；成片

我是C++世界的新手，正在尝试将文件流写入磁盘。我能够做到以下几点：

  const Aws::String objectKey2("filename.tar");
  Aws::S3::S3Client s3_client2;
  Aws::S3::Model::GetObjectRequest object_request2;
  object_request2.SetBucket(bucket_name);
  object_request2.SetKey(objectKey2);
  Aws::S3::Model::GetObjectOutcome get_object_outcome2 =
      s3_client2.GetObject(object_request2);
  auto &retrieved_file2 = get_object_outcome2.GetResult().GetBody();


  std::ios_base::sync_with_stdio(false);
  auto myfile = std::fstream("file.tar", std::ios::out | std::ios::binary);
  myfile.write((char*) &retrieved_file2, 1024*100);
  myfile.close();

但这是在向磁盘写入约1k的数据，文件无法读取（显然）。该文件是来自aws s3的tar，我尝试将其分块写入磁盘。

给出以下内容

auto &retrieved_file2 = get_object_outcome2.GetResult().GetBody();

retrieved\u file2

实际上是类型

Aws:：IOStream&

with via

typedef std::basic_iostream<char, std::char_traits<char>> Aws::IOStream;

std::fstream myfile("file.tar", std::ios::out | std::ios::binary);
myfile << retrieved_file2.rdbuf();