Move constructor and move assignement operator for class

Question

Im trying to compile the following code for an embedded device (Its a crosscompiler from TI with experimental support of C++11 (C++0)). Target:

arm-arago-linux-gnueabi Thread model: posix gcc version 4.5.3 20110311 (prerelease) (GCC)

The default specifier for the move constructor and move assignement operator cannot be compiled (/home/user/test/main.cpp:40:26: error: 'th& th::operator=(th&&)' cannot be defaulted).

std::make_unique & emplace_back are not implemented, those not usable.

What do I need to change in the code to make it work for this platform?

class th {
    public:
        void func() {
            sleep(3);
            *this->progress = 100;
        }

        th(int* prog) :
            progress(prog), 
            m_thread(std::thread(&th::func, this)) {};

        th(th const& other) = delete;
        th(th && other) = default;
        th& operator=(th const& other) = delete;
        th& operator=(th &&) = default;

        void join() { m_thread.join(); }
        int *progress;

    private:
        std::thread m_thread;
};

int main(void) {

        std::vector<int> progress;
        progress.push_back(-1);
        progress.push_back(-1);

        std::deque<std::unique_ptr<th>> deq;

        std::cout << "progress[0]:" << progress[0] << std::endl;
        std::cout << "progress[1]:" << progress[1] << std::endl;

        std::cout << "executing threads..." << std::endl;

        for(size_t i = 0; i < 2; ++i) {
            deq.push_back(std::unique_ptr<th>(new th(&progress[i])));
        }

        while(true) {
            std::cout << "SIZE:" << deq.size() << std::endl;

            if(deq.size() == 0)
                break;

            for (std::deque<std::unique_ptr<th>>::iterator it = deq.begin(); it != deq.end(); it++) {
                //std::cout << (*it)->progress << std::endl;
                if(*((*it)->progress) == 100) {
                    std::cout << "JOIN & DELETE" << std::endl;
                    (*it)->join();
                    deq.erase(it);
                }
                else {
                    std::cout << "STILL RUNNING" << std::endl;
                }
                    //std::cout << *((*it)->progress) << std::endl;
            }
            sleep(1);
        }

    exit(EXIT_SUCCESS);
}

Answer 1

gcc 4.5.x does not support the generation of move special member functions, see N3053 for more details, and also https://gcc.gnu.org/gcc-4.5/cxx0x_status.html for the gcc C++11 support features, so you're out of luck with the compiler. Your code compiles fine on gcc5/6 and clang, see it live here.

One option is to remove altogether the lines

th(th const& other) = delete;
th(th && other) = default;
th& operator=(th const& other) = delete;
th& operator=(th &&) = default;

and let the compiler do the work and generate the special member functions for you. BTW, the copy ctor and copy assignment operator will be deleted by default, as std::thread is non-copyable.