[英]boost::bind doesn't work with pointer argument
I have this simple program. 我有这个简单的程序。 Here I try to bind member function with object and call later on with arguments required in member function call.
在这里,我尝试将成员函数与对象绑定,然后使用成员函数调用中所需的参数调用。 When the member function taken a pointer to integer , gcc fails to compile.
当成员函数采用指向整数的指针时 ,gcc无法编译。 With integer parameter the program gets compiled.
使用整数参数,程序被编译。 Is this a bug with boost::bind or am I missing something?
这是boost :: bind的错误还是我错过了什么?
// Doesn't work with pointer
#include <iostream>
#include <boost/bind.hpp>
using namespace std;
using namespace boost;
struct X
{
float f_;
float& f(int *aa) {
cout << *aa << endl;
return f_;
}
};
int main() {
X x;
x.f_=200.1;
int j = 10;
cout << bind(&X::f, ref(x), _1)(&j) << endl;
}
ERROR:
member.cpp: In function ‘int main()’:
member.cpp:22: error: no match for call to ‘(boost::_bi::bind_t<float&, boost::_mfi::mf1<float&, X, int*>, boost::_bi::list2<boost::reference_wrapper<X>, boost::arg<1> > >) (int*)’
/usr/include/boost/bind/bind_template.hpp:17: note: candidates are: typename boost::_bi::result_traits<R, F>::type boost::_bi::bind_t<R, F, L>::operator()() [with R = float&, F = boost::_mfi::mf1<float&, X, int*>, L = boost::_bi::list2<boost::reference_wrapper<X>, boost::arg<1> >]
/usr/include/boost/bind/bind_template.hpp:23: note: typename boost::_bi::result_traits<R, F>::type boost::_bi::bind_t<R, F, L>::operator()() const [with R = float&, F = boost::_mfi::mf1<float&, X, int*>, L = boost::_bi::list2<boost::reference_wrapper<X>, boost::arg<1> >]
/usr/include/boost/bind/bind_template.hpp:29: note: typename boost::_bi::result_traits<R, F>::type boost::_bi::bind_t<R, F, L>::operator()(A1&) [with A1 = int*, R = float&, F = boost::_mfi::mf1<float&, X, int*>, L = boost::_bi::list2<boost::reference_wrapper<X>, boost::arg<1> >]
/usr/include/boost/bind/bind_template.hpp:35: note: typename boost::_bi::result_traits<R, F>::type boost::_bi::bind_t<R, F, L>::operator()(A1&) const [with A1 = int*, R = float&, F = boost::_mfi::mf1<float&, X, int*>, L = boost::_bi::list2<boost::reference_wrapper<X>, boost::arg<1> >]
// Works fine
#include <iostream>
#include <boost/bind.hpp>
using namespace std;
using namespace boost;
struct X
{
float f_;
float& f(int aa) {
cout << aa << endl;
return f_;
}
};
int main() {
X x;
x.f_=200.1;
int j = 10;
cout << bind(&X::f, ref(x), _1)(j) << endl;
}
bind的第一个参数应该是指向要将非静态方法应用于的对象的指针:
cout << bind(&X::f, &x, _1)(&j) << endl;
I have tested that the problem code works with boost 1.40 and gcc 4.4.3. 我测试过问题代码适用于boost 1.40和gcc 4.4.3。 I made further changes to test some more scenarios and they all work.
我做了进一步的更改以测试更多场景,它们都有效。 The following piece of code works perfectly.
下面这段代码完美 。
#include <iostream>
#include <boost/shared_ptr.hpp>
#include <boost/bind.hpp>
using namespace std;
using namespace boost;
struct X
{
float f_;
float& f(shared_ptr<int> aa) {
cout << *aa << endl;
return f_;
}
};
struct XX
{
float f_;
float& f(int* aa) {
cout << *aa << endl;
return f_;
}
};
struct XXX
{
float f_;
float& f(int* aa, int a) {
cout << *aa << " " << a << endl;
return f_;
}
};
int main() {
X x;
XX xx;
XXX xxx;
xx.f_ = 2000.11;
xxx.f_ = 20.11;
shared_ptr<X> p(new X);
x.f_=200.1;
p->f_=20000.11;
int i = 5;
int j = 10;
shared_ptr<int> sh(new int(100));
x.f(sh);
cout << bind(&X::f, ref(x), _1)(sh) << endl; // x.f(i)
cout << bind(&X::f, &x, _1)(sh) << endl; //(&x)->f(i)
cout << bind(&X::f, x, _1)(sh) << endl; // (internal copy of x).f(i)
cout << bind(&X::f, p, _1)(sh) << endl; // (internal copy of p)->f(i)
cout << bind(&XX::f, ref(xx), _1)(&j) << endl; // x.f(i)
cout << bind<float&>(mem_fn(&XXX::f), ref(xxx), _1, _2)(&j, i) << endl; // x.f(i)
}
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