[C++0x unique_ptr] sorting a vector of unique_ptr fails

[C++0x unique_ptr] sorting a vector of unique_ptr fails

[René Bürgel]

Hello!

Is the following code supposed to work in C++0x-Mode or am i just doing 
something wrong?

#include <memory>
#include <vector>
#include <algorithm>

int main()
{
        std::vector<std::unique_ptr<int> > v;
        std::sort(v.begin(), v.end());
}


g++-4.4.0-alpha20081107 -std=c++0x bug.cpp gives me:

In file included from 
/usr/lib/gcc/i686-pc-linux-gnu/4.4.0-alpha20081107/include/g++-v4/algorithm:67,
                 from 
../../bug.cpp:3:                                                               

/usr/lib/gcc/i686-pc-linux-gnu/4.4.0-alpha20081107/include/g++-v4/bits/unique_ptr.h: 
In function 'void std::__introsort_loop(_RandomAccessIterator, 
_RandomAccessIterator, _Size) [with _RandomAccessIterator = 
__gnu_cxx::__normal_iterator<std::unique_ptr<int, 
std::default_delete<int> >*, std::vector<std::unique_ptr<int, 
std::default_delete<int> >, std::allocator<std::unique_ptr<int, 
std::default_delete<int> > > > >, _Size = 
int]':                                                                   
/usr/lib/gcc/i686-pc-linux-gnu/4.4.0-alpha20081107/include/g++-v4/bits/stl_algo.h:5152:   
instantiated from 'void std::sort(_RAIter, _RAIter) [with _RAIter = 
__gnu_cxx::__normal_iterator<std::unique_ptr<int, 
std::default_delete<int> >*, std::vector<std::unique_ptr<int, 
std::default_delete<int> >, std::allocator<std::unique_ptr<int, 
std::default_delete<int> > > > >]'      
../../bug.cpp:10:   instantiated from 
here                                                                                   

/usr/lib/gcc/i686-pc-linux-gnu/4.4.0-alpha20081107/include/g++-v4/bits/unique_ptr.h:215: 
error: deleted function 'std::unique_ptr<_Tp, 
_Tp_Deleter>::unique_ptr(const std::unique_ptr<_Tp, _Tp_Deleter>&) [with 
_Tp = int, _Tp_Deleter = 
std::default_delete<int>]'                                                                                                                    

/usr/lib/gcc/i686-pc-linux-gnu/4.4.0-alpha20081107/include/g++-v4/bits/stl_algo.h:2249: 
error: used here
[...]


Thanks in advance
René

Re: [C++0x unique_ptr] sorting a vector of unique_ptr fails

[Ian Lance Taylor]

René Bürgel <rbuergel@web.de> writes:

> Is the following code supposed to work in C++0x-Mode or am i just
> doing something wrong?
>
> #include <memory>
> #include <vector>
> #include <algorithm>
>
> int main()
> {
>        std::vector<std::unique_ptr<int> > v;
>        std::sort(v.begin(), v.end());
> }

I think it is supposed to work.  The standard says that the value
must be Swappable, MoveConstructible, and MoveAssignable.  I think
that std::unique_ptr meets those requirements.

I think this is a bug in libstdc++-v3.  Looking at the code, I think
this means that __introsort_loop can't assume that it can pass values
to std::__median.

Ian

Re: [C++0x unique_ptr] sorting a vector of unique_ptr fails

[Christopher Jefferson]

On 15 Dec 2008, at 19:28, Ian Lance Taylor wrote:

> René Bürgel <rbuergel@web.de> writes:
>
>> Is the following code supposed to work in C++0x-Mode or am i just
>> doing something wrong?
>>
>> #include <memory>
>> #include <vector>
>> #include <algorithm>
>>
>> int main()
>> {
>>       std::vector<std::unique_ptr<int> > v;
>>       std::sort(v.begin(), v.end());
>> }
>
> I think it is supposed to work.  The standard says that the value
> must be Swappable, MoveConstructible, and MoveAssignable.  I think
> that std::unique_ptr meets those requirements.
>
> I think this is a bug in libstdc++-v3.  Looking at the code, I think
> this means that __introsort_loop can't assume that it can pass values
> to std::__median.


It is a "bug" in that not all of libstdc++-v3 has been updated to C+ 
+0x. Sort is one such example.

Chris

Re: [C++0x unique_ptr] sorting a vector of unique_ptr fails

[René Bürgel]

Christopher Jefferson schrieb:
>
> On 15 Dec 2008, at 19:28, Ian Lance Taylor wrote:
>
>> René Bürgel <rbuergel@web.de> writes:
>>
>>> Is the following code supposed to work in C++0x-Mode or am i just
>>> doing something wrong?
>>>
>>> #include <memory>
>>> #include <vector>
>>> #include <algorithm>
>>>
>>> int main()
>>> {
>>>       std::vector<std::unique_ptr<int> > v;
>>>       std::sort(v.begin(), v.end());
>>> }
>>
>> I think it is supposed to work.  The standard says that the value
>> must be Swappable, MoveConstructible, and MoveAssignable.  I think
>> that std::unique_ptr meets those requirements.
>>
>> I think this is a bug in libstdc++-v3.  Looking at the code, I think
>> this means that __introsort_loop can't assume that it can pass values
>> to std::__median.
>
>
> It is a "bug" in that not all of libstdc++-v3 has been updated to 
> C++0x. Sort is one such example.
>
> Chris
Would it be useful to file a bugreport (at least for keeping track of 
this) or can this fact be assumed to be commonly known by the 
responsible persons, meaning that it is on their todo-list anyway? Maybe 
i can take a closer look at this during the xmas holiday and create a 
patch to fix this issue. Would this need any paperworks with the FSF?

René

Re: [C++0x unique_ptr] sorting a vector of unique_ptr fails

[Ian Lance Taylor]

René Bürgel <rbuergel@web.de> writes:

> Maybe i can take a closer look at this during the xmas holiday and
> create a patch to fix this issue. Would this need any paperworks with
> the FSF?

Yes, a patch for this would require paperwork with the FSF.  If you
are interested, let me know, and I will send you what you need to
start the process.  Thanks.

Ian

Re: [C++0x unique_ptr] sorting a vector of unique_ptr fails

[René Bürgel]

> If you
> are interested, let me know, and I will send you what you need to
> start the process.  Thanks.
>
> Ian
>   
Thanks, i'd appreciate that.
Is there anyone, that can act as a kind of mentor, just for the case, 
that some questions will come up? I consider myself still as a junior 
software developer, although i'm quite experienced in C++ including a 
good understandig of template metaprogramming.

René

Re: [C++0x unique_ptr] sorting a vector of unique_ptr fails

[Diego Novillo]

On Tue, Dec 16, 2008 at 19:44, René Bürgel <rbuergel@web.de> wrote:

> Is there anyone, that can act as a kind of mentor, just for the case, that
> some questions will come up? I consider myself still as a junior software
> developer, although i'm quite experienced in C++ including a good
> understandig of template metaprogramming.

There are three main resources you can use:

1- Wiki: http://gcc.gnu.org/wiki/GettingStarted has links to some
internal documentation, presentations, papers, etc.
2- IRC: irc://irc.oftc.net/#gcc: several of us hang out in that
channel and you'll usually find somebody to answer your question or
point you in the general direction.
3- Mailing lists: You can mail your question to gcc@gcc.gnu.org, this
may take longer than the other 2, but is also a good resource.


Diego.

Re: [C++0x unique_ptr] sorting a vector of unique_ptr fails

[Diego Novillo]

On Tue, Dec 16, 2008 at 19:44, René Bürgel <rbuergel@web.de> wrote:

> Is there anyone, that can act as a kind of mentor, just for the case, that
> some questions will come up? I consider myself still as a junior software
> developer, although i'm quite experienced in C++ including a good
> understandig of template metaprogramming.

There are three main resources you can use:

1- Wiki: http://gcc.gnu.org/wiki/GettingStarted has links to some
internal documentation, presentations, papers, etc.
2- IRC: irc://irc.oftc.net/#gcc: several of us hang out in that
channel and you'll usually find somebody to answer your question or
point you in the general direction.
3- Mailing lists: You can mail your question to gcc@gcc.gnu.org, this
may take longer than the other 2, but is also a good resource.


Diego.