C ++花式模板代码问题 [英] C++ fancy template code problem

问题描述

我有一个（对我来说）相当复杂的模板代码结构：
a class shaderProperty of generic type

  class IShaderProperty {
 public：
 virtual〜IShaderProperty（）{} 
}; 
 
 struct IShaderMatth; // forward declaration 
 template< typename ShadeType> 
 struct ShaderMatth; // forward declaration 
 
 template< typename T> 
 class ShaderProperty：public IShaderProperty 
 {
 public：
 
 template< typename SomeType> 
 inline T getValue（ShaderMatth< SomeType> * shaderMatth）{
 pair< map< void *，IShaderMatth> :: iterator，bool& success = shaderMatth-> properties.insert（make_pair（（void *）this，ShaderMatth< T>（m_shader）））; 
 assert（success.second）; 
 return m_shader-> shade（（ShaderMatth< T> *）&（* success.first））; 
} 
 
}; 
 

和类ShaderMatth，它也是泛型类型，并存储映射，而void *指针用作键实际上是一个指向ShaderProperty的指针。 ShaderMatth代码：

  #includeShaderProperty.h
 
 struct IShaderMatth {
 virtual〜IShaderMatth（）{} 
 map< void *，IShaderMatth>属性; 
 ... 
}; 
 
 template< class ReturnType> 
 struct ShaderMatth：public IShaderMatth {
 ShaderMatth（IShader< ReturnType> * shaderPtr）{shader = shaderPtr}; 
〜ShaderMatth（void）; 
 IShader< ReturnType> * shader; 
}; 
  

现在错误发生在函数内联T的第一行T getValue（）

我得到一个

 错误C2027使用未定义类型'ShaderMatth< ShadeType>'
  

但我不明白为什么..我有正向声明的模板struct ShaderMatth，

我挂了 - 请帮助：）

解决方案

转发声明 ShaderMatth 不足以使用代码 shaderMatth - >属性。

必须在该行之前定义。

I try to get a (for me) rather complex construct of templated code to work.

what i have: a class shaderProperty of generic type

class IShaderProperty {
public:
virtual ~IShaderProperty() {}
};

struct IShaderMatth; //forward declaration
template<typename ShadeType>
struct ShaderMatth;//forward declaration

template <typename T> 
class ShaderProperty : public IShaderProperty
{
public:

 template <typename SomeType>
 inline T getValue(ShaderMatth<SomeType>* shaderMatth){
 pair<map<void*, IShaderMatth>::iterator,bool> success = shaderMatth->properties.insert(make_pair((void*)this, ShaderMatth<T>(m_shader)));
 assert(success.second);
 return m_shader->shade((ShaderMatth<T>*)&(*success.first));
 }

};

and the class ShaderMatth, which is also of generic type, and stores a map whereas the void* pointer used as key is actually a pointer to a ShaderProperty. Code for ShaderMatth:

#include "ShaderProperty.h"

struct IShaderMatth {
 virtual ~IShaderMatth() {}
 map<void*, IShaderMatth> properties;
...
};

template <class ReturnType> 
struct ShaderMatth : public IShaderMatth{
 ShaderMatth(IShader<ReturnType>* shaderPtr){shader=shaderPtr};
 ~ShaderMatth(void);
 IShader<ReturnType>* shader;
};

now the error occurs on the first line of function inline T getValue()

i get an

Error C2027 use of undefined type 'ShaderMatth<ShadeType>'

but i don't understand why.. I have the forward declaration of templated struct ShaderMatth, and in the second bunch of code i include the first bunch of code, so the forward reference should work out, no?

I'm hanging - please help :)

解决方案

Forward declaring ShaderMatth is not enough to use the code shaderMatth->properties.

It must be defined before that line.

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