Hello here is a test code I wrote on MSVC12.
Could someone tell me why the std::move when I pass parameters to the thread are not converting the variabes to RValue refs?? And what I should do.
Thank you!
///some arbitrary long task
std::string DumpFile(std::string path){
std::this_thread::sleep_for(std::chrono::seconds(10));
return path;
}
void run_promise(std::promise<std::string> &&_prom, std::string &&_path){
try {
std::string val = DumpFile(std::move(_path));
_prom.set_value(val);
}
catch (...) {
_prom.set_exception(std::current_exception());
}
}
std::future<std::string> ADumpFile(std::string && path) {
std::promise<std::string> prms;
std::future<std::string> fut = prms.get_future();
std::thread th(run_promise, std::move(prms), std::move(path));
th.detach();
return fut;
}
int main(int argc, char* argv []){
auto fut = ADumpFile("toto");
while (fut.wait_for(std::chrono::seconds(1))!=std::future_status::ready){
std::cout << "waiting\n";
}
auto res = fut.get();
getchar();
return 0;
}
The error I get is :
Error 1 error C2664: 'void (std::promise<std::string> &&,std::string &&)' : cannot convert argument 2 from 'std::basic_string<char,std::char_traits<char>,std::allocator<char>>' to 'std::string &&' C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\functional 1149 1 demo11
Error 2 error C2664: 'void (std::promise<std::string> &&,std::string &&)' : cannot convert argument 1 from 'std::promise<std::string>' to 'std::promise<std::string> &&' C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\functional 1149 1 demo11
Although, if I call run_promise(std::move(prom),std::move(path))
I have no problem.
Is this an issue related to passing the rvalue arguments through the thread CTOR?