test_mkdir.cpp

#include <iostream>
#include <boost/filesystem.hpp>

namespace fs = boost::filesystem;

int main() {
    const fs::path path("dir");
    boost::system::error_code error;
    const bool result = fs::create_directory(path, error);
    if (!result || error) {
        std::cout << "failed creating directory" << std::endl;
    }
}

g++ -l boost_filesystem -l boost_system test_mkdir.cpp