error: ‘cbegin’ was not declared in this scope

I am currently facing a problem with this code:

auto first_open(std::find(cbegin(line), cend(line), '<'));

This is the overall code:

class DLNA
{
public:
    std::string IPAddress;

    auto createMap()
    {
        std::cout << "opening file" << std::endl;
        std::ifstream myfile("newcontent.xml");

        std::cout << "checking file state" << std::endl;
        if (myfile.is_open())
        {
            std::cout << "file is open" << std::endl;

            std::map<std::string, val_t> varmap;
            varmap["IPAddress"] = &IPAddress;

            std::cout << "reference assigned" << std::endl;

            std::vector<std::string> lines;
            while(myfile.good())
            {
                std::string line;
            getline(myfile,line, '\r');
                lines.push_back(line);
            }

            std::cout << "lines size is: " << lines.size() << std::endl;

            for(const std::string& line : lines)
            {
                std::cout << "reading line:" << std::endl << line << std::endl;
            if((line.find("<") != std::string::npos) && (line.find(">")!= std::string::npos)) 
                {
                   std::cout << "brackets found" << std::endl;
                    auto first_open(std::find(cbegin(line), cend(line), '<'));
                 }
               }
           }
        }

Basically, line is just a line from a xml file and will look something like this:

<IPAddress> 123.45.67 </IPAddress>

I am compiling this program like this:

c++ -I boost_1_59_0 anothertry.cpp -o variant -std=c++1y

Any reason why this isn't working?

Thanks.

via Chebli Mohamed