Using Boost adaptors with C++11 lambdas

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I tried to compile this code:

#include <boost/range/adaptors.hpp>
#include <boost/range/algorithm.hpp>
#include <vector>

int main() {
    std::vector<int> v{
        1,5,4,2,8,5,3,7,9
    };
    std::cout << *boost::min_element(v | boost::adaptors::transformed(
            [](int i) { return -i; })) << std::endl;
    return 0;
}

The compilation failed with the following error message (after a long template instantiation novel):

/usr/local/include/boost/iterator/transform_iterator.hpp:84:26: error: use of deleted function ‘main()::<lambda(int)>::<lambda>()’
../main.cpp:12:5: error: a lambda closure type has a deleted default constructor

I googled the problem, and found this in the Boost Users mailing list archive. It suggested that using #define BOOST_RESULT_OF_USE_DECLTYPE would solve the problem. I put it into the very beginning of my code, but it still doesn't compile. The length of the error message seems to be much shorter, but the error message at the end is the same. I'm currently using Boost 1.50.

What can be the problem here? Is there any way to make this work?

boost-range c++11 lambda boost c++
4 Answers

With C++17 feature class template argument deduction you can wrap with std::function simplier, like this:

*boost::min_element(
    v | boost::adaptors::transformed(std::function(
        [](int i) { return -i; })));
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