SFML and C++0x; "error: use of deleted function"

[unranked86]

Hi there!

As some of you may know I'm still a beginner with C++, so sometimes I got newbie questions.
Let's suppose, I have this object:

Code: [Select]

class aClass
{
public:
   aClass () { // initialize stuff }

    void Update () { // update stuff, not relevant }

    void Draw (const sf::RenderTarget& target)
    {
         Sprite.Draw(target);
    }

private:
    sf::Sprite Sprite;
};

I have a few of this object in a vector:

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std::vector<aClass> vec;

So, I was experimenting with for_each and std::mem_fun_ref, and I came up with this:

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// win is a sf::RenderWindow object
for_each(vec.begin(), vec.end(), std::mem_fun_ref(&aClass::Update));

for_each(vec.begin(), vec.end(), std::bind(std::mem_fun_ref(&aClass::Draw), win));

I compile it with -std=c++0x using g++ (4.6, so it supports C++0x), under Linux, and I got a nice error message, "error: use of deleted function" at the second line. After a bit of Google, I really didn't get a good answer. I think, it is because the sf::RenderWindow is a non-copyable class, which is the base class of sf::RenderTarget. Is this correct ? Or I'm doing it in a wrong way ?
Because, if I use a "classic" for loop, it compiles just fine. (note: the first line compiles without any error, and does what it should do in both cases)

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std::vector<aClass>::iterator iter;
for (iter = vec.begin(); iter != vec.end(); ++iter)
{
   iter->Draw(win);
}

[Laurent]

Try to pass std::ref(win) instead of win. So that it is not copied.

[unranked86]

That seems to be not working. Here is a minimal example.

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#include <functional>
#include <vector>

#include <SFML/Graphics.hpp>

class entity
{
public:
entity (int x)
{
sf::FloatRect rect(x, 50, 50, 50);
Shape = sf::Shape::Rectangle(rect, sf::Color::Red);
}

void update ()
{
}

void draw (sf::RenderTarget& target)
{
target.Draw(Shape);
}

private:
sf::Shape Shape;

};

int main ()
{
std::vector<entity> ents;

sf::RenderWindow win(sf::VideoMode(640, 480, 32), "test", sf::Style::Close);

entity en1(0);
entity en2(50);
entity en3(150);

ents.push_back(en1);
ents.push_back(en2);
ents.push_back(en3);

while (win.IsOpened())
{
sf::Event event;

while (win.PollEvent(event))
{
if (event.Type == sf::Event::Closed)
win.Close();
}

win.Clear(sf::Color::Black);

for_each(ents.begin(), ents.end(), std::mem_fun_ref(&entity::update));

for_each(ents.begin(), ents.end(), std::bind(std::mem_fun_ref(&entity::draw), std::ref(win)));

win.Display();
}

return 0;
}

It still won't compile. I get a different error, which is....cryptic to me

[Laurent]

I get a different error

Which is... ?

And why are you still using std::mem_fun_ref if you have the almighty std::bind?
I can't try, but something like this should work:

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for_each(ents.begin(), ents.end(), std::bind(&entity::update, _1));

for_each(ents.begin(), ents.end(), std::bind(&entity::draw, _1, std::ref(win)));

[unranked86]

I get a different error

Which is... ?

And why are you still using std::mem_fun_ref if you have the almighty std::bind?
I can't try, but something like this should work:

Code: [Select]

for_each(ents.begin(), ents.end(), std::bind(&entity::update, _1));

for_each(ents.begin(), ents.end(), std::bind(&entity::draw, _1, std::ref(win)));

Thanks a lot, it compiles now Is there any beginner friendly documentation about the new features of C++? I can't find one. I checked the gcc one, but it's a bit hard for me to read.

I'm sorry, but I can't copy the error message

[Nehmulos]

 Is there any beginner friendly documentation about the new features of C++? I can't find one. I checked the gcc one, but it's a bit hard for me to read.

The English wikipedia has a very nice article, which contains many examples, about the new features in C++11 (former C++0x) see: http://en.wikipedia.org/wiki/C%2B%2B11

[ratzlaff]

There are some good articles over at codeproject that highlight the new features of c++11

[Nexus]

C++Next has some good articles (especially concerning move semantics), too.