How to pass structure with template variable as an argument inside member function of class in c ?-CodePudding

I would like to pass 'structure with template variable' as an argument inside member function of class. I am getting error "no matching function for call to". Can anyone help me? I am doing some mistake either in declaration / definition / while passing argument from the main.

template <typename T>
struct msg_1{
   int var_1;
   int var_2;
   T *var_3;
};

template<typename T>
struct msg_2{
    int var_1;
    int var_2;
    T *var_3;
};

class A
{
 public:
  int a;
  int b;

  template <typename T>
  void test(T *, T *);
 };

 template <typename T>
 void A::test(T *t1, T *t2)
 {      cout<<"Inside test @todo Do something"; }

int main()
{
 A ob;
 ob.a=10;
 ob.b=20;

 msg_1<int> *ob_1 = new msg_1<int>;
 msg_2<int> *ob_2 = new msg_2<int>;

 ob.test(ob_1,ob_2);

 return 0;
}

======== I have accepted the given suggestion and modified the code, but getting some error while implementing. Kindly have a look.

I have passed the structure as a parameter in test method like below

template <typename T>
struct msg1{
…
};

template<typename U>
struct msg2{
…
};

struct msg3
{
uint16_t var_4;
};

class A
{
 public:
 int a;
 int b;

 template <typename T, typename U>
 void test(msg1<T> *t1, msg2<U> *t2);
};

template <typename T, typename U>
void A::test(msg1<T> *t1, msg2<U> *t2)
{
 cout<<"Inside test @todo Do something";
}

int main()
{
 A ob;
 ob.a=10;
 ob.b=20;

 msg_1<msg3> *ob_1 = new msg_1<msg3>;
 msg_2<msg3> *ob_2 = new msg_2<msg3>;

 ob.test(ob_1,ob_2);

 return 0;
 }

When I am running above code in online compiler then it’s running fine but when I am implementing it in actual code to do testing then I am getting compile time error “undefined reference to ‘void A::test< msg3, msg3 > ( msg1 *, msg2 * )’. Can anyone please tell me what possibly I am doing wrong.

CodePudding user response：

Your template function A::test is only templated with one type T and requires that both parameters have the same type T*. In your example you pass different parameters: msg_1<int> * and msg_2<int> *.

If you really want test to only accept two parameters with identical type, then you can't pass ob_1 and ob_2. If you want test to accept two parameters of different type, then you can change your class A and function A::test as follows.

class A
{
public:
  int a;
  int b;

  template <typename T1, typename T2>
  void test(T1 *, T2 *);
};

template <typename T1, typename T2>
void A::test(T1 *t1, T2 *t2)
{ cout<<"Inside test @todo Do something"; }