[parameter] compiler errors with operator()

10 May 2010

      Hello all,

I am trying to compile the example from Boost.Parameter section 2.2
but I get the GCC errors below. The errors go aways if I name the
member function `f` instead of `operator()`.

What am I doing wrong? How do I use Boost.Parameter with member operators?

    // File: "c2.cpp".
    #include <boost/parameter.hpp>
    #include <iostream>

    BOOST_PARAMETER_NAME(arg1)
    BOOST_PARAMETER_NAME(arg2)

    struct callable2
    {
        BOOST_PARAMETER_CONST_MEMBER_FUNCTION(
            (void), operator(), tag, (required (arg1,(int))(arg2,(int))))
        {
            std::cout << arg1 << ", " << arg2 << std::endl;
        }
    };

    int main() {
        callable2 c2;
        c2(1, 2);
        c2(2, 1);
        return 0;
    }

$ g++ -Wall -Werror example/Own/parameter/c2.cpp
example/Own/parameter/c2.cpp:10: error: expected unqualified-id before ‘)’ token
example/Own/parameter/c2.cpp:10: error: expected unqualified-id before ‘)’ token
example/Own/parameter/c2.cpp:10: error: expected unqualified-id before ‘)’ token
example/Own/parameter/c2.cpp:10: error: expected nested-name-specifier
before ‘boost_param_result_11operator’
example/Own/parameter/c2.cpp:10: error: expected initializer before ‘<’ token
example/Own/parameter/c2.cpp:10: error: expected nested-name-specifier
before ‘boost_param_result_11operator’
example/Own/parameter/c2.cpp:10: error: expected initializer before ‘<’ token
example/Own/parameter/c2.cpp:10: error:
‘boost_param_default_11operator’ declared as function returning a
function
example/Own/parameter/c2.cpp: In member function ‘int
callable2::boost_param_default_11operator()’:
example/Own/parameter/c2.cpp:13: error: ‘arg1’ was not declared in this scope
example/Own/parameter/c2.cpp:13: error: ‘arg2’ was not declared in this scope
cc1plus: warnings being treated as errors
example/Own/parameter/c2.cpp:14: warning: no return statement in
function returning non-void
example/Own/parameter/c2.cpp: In function ‘int main()’:
example/Own/parameter/c2.cpp:19: error: no match for call to
‘(callable2) (int, int)’
example/Own/parameter/c2.cpp:20: error: no match for call to
‘(callable2) (int, int)’

$ g++ --version
g++ (GCC) 4.2.4 (Ubuntu 4.2.4-1ubuntu4)

I am using Boost v1.42.0

Thank you very much.

-- 
Lorenzo

P.S. Shall I report these type of questions on this mailing list or in
Boost's TRAC? I am new to Boost.Parameter so I am not sure these are
actual bugs...

Lorenzo Caminiti

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