我刚刚想出了一个想法来构建一个简单的信号库实现,比如 boost::signals。
我为此编写了一个简单的模板,但是在尝试调用 oparator() 以触发所有回调时出现错误:
template <typename funcDef>
struct Connection
{
typename std::vector<std::function<funcDef>>::iterator connectionItem;
};
template <typename funcDef>
class Signal;
template <typename retType, typename... args>
class Signal<retType(args...)>
{
using return_type = retType;
using argument_type = std::tuple<args...>;
public:
Signal() {};
~Signal() {};
Connection<retType(args...)> connect(std::function<retType(args...)> callback)
{
Connection<retType(args...)> connection;
m_callbacks.push_back(callback);
connection.connectionItem = std::prev(m_callbacks.end());
return connection;
}
void disconnect(Connection<retType(args...)> connection) { m_callbacks.erase(connection.connectionItem); }
void operator() (args...)
{
for (const auto & cb : m_callbacks)
cb(args...); // this generates compiler error: Error C2062 type 'int' unexpected
}
private:
std::vector<std::function<retType(args...)>> m_callbacks;
};
int sum(int a, int b){ return a + b; }
int sub(int a, int b){ return a - b; }
int main()
{
Signal<int(int, int)> sig;
auto c1 = sig.connect(sum);
auto c2 = sig.connect(sub);
sig(2, 2);
return 0;
}
任何想法此编译器错误的原因是什么(错误 C2062 类型“int”意外)