Re: [Boost-users] Tuple operator==

From: Alexander Ivanov (amivanov_at_[hidden])
Date: 2005-11-23 18:23:50

On 11/23/05, Josue Gomes <josue.gomes.honeypot_at_[hidden]> wrote:
> Hi,
>
> Take this code:
>
> #include <string>
> #include <boost/tuple/tuple.hpp>

#include <boost/tuple/tuple_comparison.hpp>

>
> struct A {};
>
> bool operator==(A, A) { return true; }
>
> int main()
> {
>         using namespace boost;
>
>         tuple<std::string, int, A> t1(std::string("same?"), 2, A());
>         tuple<std::string, long, A> t2(std::string("same?"), 2, A());
>         tuple<std::string, long, A> t3(std::string("different"), 3, A());
>
>         t1 == t2;               // error: no match for operator==
>         t1 == t3;               // error: no match for operator==
> }
>
>
> This is similar to the example shown in Boost.Tuple docs. However the
> compiler(*) refuses to compile it.
> I tried it with versions 1.33.0 and 1.33.1 (Beta)
>
> Any ideas?
>
> Compiler outputs below:
>
> MSC C/C++ Compiler 13.10;3077
>
>         cl /GR /EHsc /IE:\projects\libraries\boost_1_33_1 tuple_error.cpp
> Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 13.10.3077 for 80x86
> Copyright (C) Microsoft Corporation 1984-2002. All rights reserved.
>
> tuple_error.cpp
> tuple_error.cpp(17) : error C2678: binary '==' : no operator found which takes a
>  left-hand operand of type 'boost::tuples::tuple<T0,T1,T2>' (or there is no acce
> ptable conversion)
>         with
>         [
>             T0=std::string,
>             T1=int,
>             T2=A
>         ]
> tuple_error.cpp(18) : error C2678: binary '==' : no operator found which takes a
>  left-hand operand of type 'boost::tuples::tuple<T0,T1,T2>' (or there is no acce
> ptable conversion)
>         with
>         [
>             T0=std::string,
>             T1=int,
>             T2=A
>         ]
>
>
> gcc 3.4.4
>
>         g++ -I E:\projects\libraries\boost_1_33_1 tuple_error.cpp -o
> tuple_error_gcc.exe
> tuple_error.cpp: In function `int main()':
> tuple_error.cpp:17: error: no match for 'operator==' in 't1 == t2'
> tuple_error.cpp:7: note: candidates are: bool operator==(A, A)
> tuple_error.cpp:18: error: no match for 'operator==' in 't1 == t3'
> tuple_error.cpp:7: note: candidates are: bool operator==(A, A)
>
>
> Regards,
> Josue
>
> _______________________________________________
> Boost-users mailing list
> Boost-users_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-users
>