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[英]c++ using namespace std causes errors with bind () and a waiver with the iterator
[英]Using std::bind with overloaded methods in namespace in C++
#include <iostream>
#include <map>
#include <functional>
namespace xAOD{
namespace EgammaParameters{
enum ShowerShapeType{
var1 = 0,
var2 = 1,
var3 = 3
};
};
class Photon{
public:
// I don't want to use this overload
//double test(float& value, const EgammaParameters::ShowerShapeType information) const {return 1;}
// I want to use this overload
double test(const EgammaParameters::ShowerShapeType information) const {return 1;}
private:
};
};
struct funcLookup
{
funcLookup(xAOD::Photon * photon)
{
//this works without the first overload
lookup_callback["test"] = std::bind(&xAOD::Photon::test, photon, xAOD::EgammaParameters::ShowerShapeType::var1);
// static casting doesn't work:
//lookup_callback["test"] = std::bind(static_cast<double(&)(const xAOD::EgammaParameters::ShowerShapeType)>(&xAOD::Photon::test), photon,xAOD::EgammaParameters::ShowerShapeType::var1);
}
double call(std::string name)
{
if (lookup_callback.count(name) > 0){
return lookup_callback[name]();
}
else{
std::cerr << "Invalid Function Call "<< std::endl;
return -1;
}
}
std::map<std::string, std::function<double(void)>> lookup_callback;
};
int main()
{
xAOD::Photon * photon;
funcLookup funcMap(photon);
std::cout<<funcMap.call("test")<<std::endl;
return 0;
}
我正在尝试在 class Photon 的命名空间 EgammaParameters 中绑定一个方法(测试)。 据我了解,我需要特别告诉 C++ 它应该使用哪种重载方法,所以我尝试使用 static 铸造,如:
std::bind(static_cast<double(&)(const xAOD::EgammaParameters::ShowerShapeType)>(&xAOD::Photon::test), photon,xAOD::EgammaParameters::ShowerShapeType::var1);
但是,这给了我错误error: invalid static_cast from type '' to type 'double (&)(xAOD::EgammaParameters::ShowerShapeType)
。 我错过了什么?
使用 lambda 更容易:
lookup_callback["test"] = [=] {
return photon->test(xAOD::EgammaParameters::ShowerShapeType::var1);
};
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