以下代码用于从本地进行追加上传：

#include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;

int main(void)
{
    /* 初始化OSS账号信息 */
    std::string AccessKeyId = "yourAccessKeyId";
    std::string AccessKeySecret = "yourAccessKeySecret";
    std::string Endpoint = "yourEndpoint";
    std::string BucketName = "yourBucketName";
    std::string ObjectName = "yourObjectName";

    /* 初始化网络等资源 */
    InitializeSdk();

    ClientConfiguration conf;
    OssClient client(Endpoint, AccessKeyId, AccessKeySecret, conf);

    auto meta = ObjectMetaData();
    meta.setContentType("text/plain");

    /* 第一次追加的位置是0，返回值为下一次追加的位置。后续追加的位置是追加前文件的长度。*/
    std::shared_ptr<std::iostream> content1 = std::make_shared<std::stringstream>();
    *content1 <<"Thank you for using Aliyun Object Storage Service!";
    AppendObjectRequest request(BucketName, ObjectName, content1, meta);
    request.setPosition(0L);

    /*第一次追加文件*/
    auto result = client.AppendObject(request);
  
    if (!result.isSuccess()) {
        /* 异常处理 */
        std::cout << "AppendObject fail" <<
        ",code:" << result.error().Code() <<
        ",message:" << result.error().Message() <<
        ",requestId:" << result.error().RequestId() << std::endl;
        ShutdownSdk();
        return -1;
    }

    std::shared_ptr<std::iostream> content2 = std::make_shared<std::stringstream>();
    *content2 <<"Thank you for using Aliyun Object Storage Service!";
    auto position = result.result().Length();
    AppendObjectRequest appendObjectRequest(BucketName, ObjectName, content2);
    appendObjectRequest.setPosition(position);

    /*第二次追加文件*/
    auto outcome = client.AppendObject(appendObjectRequest);

    if (!outcome.isSuccess()) {
        /* 异常处理 */
        std::cout << "AppendObject fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        ShutdownSdk();
        return -1;
    }

    /*释放网络等资源*/
    ShutdownSdk();
    return 0;
}