[英]std::bind and overloaded function
Please refer the following code snippet. 请参阅以下代码段。 I want to use the std::bind
for overloaded function foobar
. 我想使用std::bind
来重载函数foobar
。 It calls only the method with no arguments. 它只调用没有参数的方法。
#include <functional>
#include <iostream>
class Client
{
public :
void foobar(){std::cout << "no argument" << std::endl;}
void foobar(int){std::cout << "int argument" << std::endl;}
void foobar(double){std::cout << "double argument" << std::endl;}
};
int main()
{
Client cl;
//! This works
auto a1 = std::bind(static_cast<void(Client::*)(void)>(&Client::foobar),cl);
a1();
//! This does not
auto a2= [&](int)
{
std::bind(static_cast<void(Client::*)(int)>(&Client::foobar),cl);
};
a2(5);
return 0;
}
You need to use placeholders
for the unbound arguments: 您需要为未绑定的参数使用placeholders
:
auto a2 = std::bind(static_cast<void(Client::*)(int)>(&Client::foobar), cl,
std::placeholders::_1);
a2(5);
You can also perform the binding with a lambda capture (note that this is binds cl
by reference, not by value): 您还可以使用lambda捕获执行绑定(请注意,这是通过引用绑定cl
,而不是通过值绑定):
auto a2 = [&](int i) { cl.foobar(i); };
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