C++ “使用” Visual Studio 2008 中的声明

发布于 2024-07-14 02:34:39 字数 1180 浏览 14 评论 0原文

我正在尝试使用 google protobuf，他们有以下示例：

using google::protobuf;

protobuf::RpcChannel* channel;
protobuf::RpcController* controller;
SearchService* service;
SearchRequest request;
SearchResponse response;

void DoSearch() {
  // You provide classes MyRpcChannel and MyRpcController, which implement
  // the abstract interfaces protobuf::RpcChannel and protobuf::RpcController.
  channel = new MyRpcChannel("somehost.example.com:1234");
  controller = new MyRpcController;

  // The protocol compiler generates the SearchService class based on the
  // definition given above.
  service = new SearchService::Stub(channel);

  // Set up the request.
  request.set_query("protocol buffers");

  // Execute the RPC.
  service->Search(controller, request, response, protobuf::NewCallback(&Done));
}

void Done() {
  delete service;
  delete channel;
  delete controller;
}

当我尝试在 Visual Studio Express 2008 中实现此代码时遇到的错误是：

错误 C2873：“google::protobuf”：符号不能用在使用声明

编辑：当我执行“using namespace google::protobuf;”时在函数内部它不再给我错误。我感到困惑的是，它并不像 Google 的示例（以及 Stroustrup 在“C++ 编程语言”中的示例）所示的那样工作。

原文

I am trying to use google protobuf and they have the following example:

using google::protobuf;

protobuf::RpcChannel* channel;
protobuf::RpcController* controller;
SearchService* service;
SearchRequest request;
SearchResponse response;

void DoSearch() {
  // You provide classes MyRpcChannel and MyRpcController, which implement
  // the abstract interfaces protobuf::RpcChannel and protobuf::RpcController.
  channel = new MyRpcChannel("somehost.example.com:1234");
  controller = new MyRpcController;

  // The protocol compiler generates the SearchService class based on the
  // definition given above.
  service = new SearchService::Stub(channel);

  // Set up the request.
  request.set_query("protocol buffers");

  // Execute the RPC.
  service->Search(controller, request, response, protobuf::NewCallback(&Done));
}

void Done() {
  delete service;
  delete channel;
  delete controller;
}

The error I am getting when I try to implement this code in Visual Studio Express 2008 is:

error C2873: 'google::protobuf' :
symbol cannot be used in a
using-declaration

Edit: When I do "using namespace google::protobuf;" inside of a function it no longer gives me the error. What I'm confused about is that it doesn't work the way that Google's example (and Stroustrup's in "The C++ Programming Language") seem to indicate.

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谈场末日恋爱 2024-07-21 02:34:39

google::protobuf 可能是一个命名空间。在这种情况下，您需要这样做。

using namespace google::protobuf;

google::protobuf is probably a namespace. In this case you need to do this.

using namespace google::protobuf;

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听，心雨的声音 2024-07-21 02:34:39

直接来自文档：

Visual C++ Concepts: Building a C/C++ Program
Compiler Error C2873
Error Message
'symbol' : symbol cannot be used in a using-declaration
A using directive is missing a namespace keyword. This causes the compiler to misinterpret the code as a using declaration rather than a using directive.

有关差异的更多信息。

Directly from the documentation:

Visual C++ Concepts: Building a C/C++ Program
Compiler Error C2873
Error Message
'symbol' : symbol cannot be used in a using-declaration
A using directive is missing a namespace keyword. This causes the compiler to misinterpret the code as a using declaration rather than a using directive.

More info on the difference.

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