How to implement class derived from templated class - c++

Question

I have solution with 2 projects inside. In first project which is builded as library I have templated class
a.h
#pragma once
#include <memory>
template<class MessageType, class HandlerType>
class A
{
std::unique_ptr<MessageType> msg;
std::unique_ptr<HandlerType> handler;
public:
A() : msg(std::make_unique<MessageType>()), handler(std::make_unique<HandlerType>()) {}
virtual ~A() {}
};
Then derived class
b.h
#include "a.h"
#include <string>
struct MyMessage
{};
struct MyHandler
{};
class B : A<MyMessage, MyHandler>
{
std::string name;
public:
B(const std::string& str);
virtual ~B();
};
and implementing it
b.cpp
#include "b.h"
B::B(const std::string& str)
{
}
B::~B()
{}
This code builded as static library (.lib). But when I try in main project to use instance of B class:
process.cpp
#include <iostream>
#include "b.h"
int main()
{
std::cout << "Hello World!\n";
B opa("yes");
}
compiler can't link it
Rebuild started...
1>------ Rebuild All started: Project: ConsoleApplication3, Configuration: Debug Win32 ------
1>b.cpp
1>ConsoleApplication3.cpp
1>Generating Code...
1>ConsoleApplication3.vcxproj -> C:\Users\user\source\repos\tmpClass\Debug\ConsoleApplication3.lib
2>------ Rebuild All started: Project: tmpClass, Configuration: Debug Win32 ------
2>process.cpp
2>process.obj : error LNK2019: unresolved external symbol "public: __thiscall B::B(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (??0B##QAE#ABV?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std###Z) referenced in function _main
2>process.obj : error LNK2019: unresolved external symbol "public: virtual __thiscall B::~B(void)" (??1B##UAE#XZ) referenced in function _main
2>C:\Users\user\source\repos\tmpClass\Debug\tmpClass.exe : fatal error LNK1120: 2 unresolved externals
2>Done building project "tmpClass.vcxproj" -- FAILED.
========== Rebuild All: 1 succeeded, 1 failed, 0 skipped ==========

Answer 1

LNK2019 means that the corresponding lib file is not added. You need to add the Lib file directory in Properties>Linker>General>Additional Library Directories and add Lib file in Properties>Linker>Input>Additional Dependencies.
Please refer to the document: Use the functionality from the static library in the app.