Mingw does not support C++ 11?

[danielmccarthy]

Hi,
I am using the Mingw compiler but this code does not work

#include <iostream>
#include <memory>
using namespace std;

int main()
{
    shared_ptr<int> sp(new int(60));

    cout << "Hello world!" << endl;
    return 0;
}

The compiler tells me shared_ptr is not declared in this scope. Does mingw not support C++ 11?

[Duthomhas]

It does, but you have to tell it to.

g++ -std=c++11 foo.cpp

Depending on the age of your compiler, you might have to specify c++0x.

Hope this helps.

[JLBorges]

Favour std::make_shared<> (exception safe, and usually more efficient) over new
http://en.cppreference.com/w/cpp/memory/shared_ptr/make_shared

// std::shared_ptr<int> sp(new int(60));
auto sp = std::make_shared<int>(20) ;

[NoXzema]

I'd say it's safer but I'm not sure where you get more efficient from...?

[Cubbi]

one allocation is more efficient than two allocations

[keskiverto]

Depending on the age of your compiler, you might have to specify c++0x.

This. Saying "using MinGW" is like saying "using car". The version of MinGW dictates what it supports, just like a version of car affects its features (Ford T-Model vs Bugatti Veyron).

MinGW is GCC and GCC supports multiple standards, but its default is conservative.

[NoXzema]

// std::shared_ptr<int> sp(new int(60));
auto sp = std::make_shared<int>(20) ;

one allocation is more efficient than two allocations

Oh, in comparison to what OP used. Apologies for not paying attention....

[danielmccarthy]

Thanks guys I toggled a compiler flag in codeblocks and now it is working

[danielmccarthy]

Using this code:

   auto sp = make_shared<int>(20);
    auto sp2 = sp;
    cout << *sp << endl;
    cout << *sp2 << endl;
    return 0;

Will automatically free the memory once all instances have left their scope?

[Duthomhas]

Yes.