Tuple operator==

23 Nov 2005

      Hi,

Take this code:

#include <string>
#include <boost/tuple/tuple.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

Josue Gomes

Alexander Ivanov

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