Failed to compile while the argument is lambda. [using hippomocks]

Question

I wrote an unit test with hippomocks, but got error while compiling it.

The compiler is VS 2010.

How can I fix it ?

#include "hippomocks.h"
#include <functional>

using namespace HippoMocks;

struct A
{
    virtual void f(std::function<void (int)> arg);
};

int main(void)
{
    MockRepository mock;
    A* aptr = mock.Mock<A>();

    mock.ExpectCall(aptr, A::f);  // error

    return 0;
}

The output is :

main.cpp
c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\INCLUDE\xlocale(323) : wa
rning C4530: C++ exception handler used, but unwind semantics are not enabled. S
pecify /EHsc
c:\users\cong\project\test\test\hippomocks.h(466) : error C2593: 'operator <<' i
s ambiguous
        c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\INCLUDE\ostream(2
06): could be 'std::basic_ostream<_Elem,_Traits> &std::basic_ostream<_Elem,_Trai
ts>::operator <<(std::_Bool)'
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        c:\users\cong\project\test\test\hippomocks.h(441): or       'std::ostrea
m &HippoMocks::operator <<(std::ostream &,const HippoMocks::NotPrintable &)'
        while trying to match the argument list '(std::ostream, std::tr1::functi
on<_Fty>)'
        with
        [
            _Fty=void (int)
        ]
        c:\users\cong\project\test\test\hippomocks.h(463) : while compiling clas
s template member function 'void HippoMocks::printArg<T>::print(std::ostream &,T
,bool)'
        with
        [
            T=std::tr1::function<void (int)>
        ]
        c:\users\cong\project\test\test\hippomocks.h(614) : see reference to cla
ss template instantiation 'HippoMocks::printArg<T>' being compiled
        with
        [
            T=std::tr1::function<void (int)>
        ]

You use no lambdas in the code above. Are you under the impression that `std::function` means lambda? — Yakk - Adam Nevraumont, Jul 07 '14 at 20:41
HippoMocks is trying to print your function (in case of a call mismatch) and it has no idea how to print an std::function, and apparently MSVC has an equally weakly binding print function for a _Bool. Best thing would be to define some way of printing an std::function, say with an operator<<. — dascandy, Aug 28 '14 at 14:06

score 0 · Answer 1 · answered Sep 22 '16 at 13:51

Enhancing @dascandy's comment here is how his method can look like. Place it after including hippomocks.h:

template<>
struct printArg<std::function<void (int)> >
{
    static inline void print(std::ostream &os, std::function<void (int)> arg, bool withComma)
    {
        if (withComma)
        {
            os << ",";
        }
        if (arg)
        {
            os << "true";
        }
        else
        {
            os << "false";
        }
    }
};

Note that I didn't test this very example but rather took our solution and adapted the type to the original post's example. I'd be happy to know whether this works for you.

Failed to compile while the argument is lambda. [using hippomocks]

1 Answers1