用HttpClient写入身体请求(Write in body request with HttpClient)

 也许如果你明确你想做什么会更好。 你为什么要创建一个未命名的类？ 它符合界面吗？ 未命名的类是非常有限的，它们不能用作函数的参数，它们不能用作模板类型参数... 
 
 现在，如果您正在实现接口，则可以将引用传递给该接口： 
 
class interface {
public:
   virtual void f() const = 0;
};
void function( interface const& o )
{
   o.f();
}
int main()
{
   class : public interface {
   public:
      virtual void f() const {
         std::cout << "bar" << std::endl;
      }
   } bar;
   function( bar ); // will printout "bar"
}
 
 注意：对于将模板参数视为选项的所有答案，未命名的类不能作为模板类型参数传递。 
 
 C ++标准。 14.3.1，第2段： 
 
 
 
 2本地类型，没有链接的类型，未命名的类型或由这些类型中的任何一种组合的类型不得用作模板类型参数的模板参数。 
 
 
 如果您使用comeau编译器进行测试（该链接用于在线试用），您将收到以下错误： 
 
 
 
 错误：模板参数可能不引用未命名的类型 
 
 
 作为旁注，comeau编译器是我所知道的最符合标准的编译器，除了是我尝试过的最有用的错误诊断之一。 
 
 注意：Comeau和gcc（g ++ 4.0）使用上面的代码给出错误。 英特尔编译器（以及其他人的评论MSVS 2008）接受使用未命名的类作为模板参数，而不是标准。 

Maybe it would be better if you explicit what you want to do. Why do you want to create an unnamed class? Does it conform to an interface? Unnamed classes are quite limited, they cannot be used as parameters to functions, they cannot be used as template type-parameters...
 
Now if you are implmenting an interface then you can pass references to that interface:
 
class interface {
public:
   virtual void f() const = 0;
};
void function( interface const& o )
{
   o.f();
}
int main()
{
   class : public interface {
   public:
      virtual void f() const {
         std::cout << "bar" << std::endl;
      }
   } bar;
   function( bar ); // will printout "bar"
}
 
NOTE: For all those answers that consider template arguments as an option, unnamed classes cannot be passed as template type arguments.
 
C++ Standard. 14.3.1, paragraph 2:
 
 
 
2 A local type, a type with no linkage, an unnamed type or a type compounded from any of these types shall not be used as a template-argument for a template type-parameter.
 
 
If you test with comeau compiler (the link is for the online tryout) you will get the following error:
 
 
 
error: a template argument may not reference an unnamed type
 
 
As a side note, comeau compiler is the most standard compliant compiler I know of, besides being the one with the most helpful error diagnostics I have tried.
 
NOTE: Comeau and gcc (g++ 4.0) give an error with the code above. Intel compiler (and from other peoples comments MSVS 2008) accept using unnamed classes as template parameters, against the standard.