错误：'无法专门化功能模板'C2893'std :: invoke'

Question

I am writing an MFC program in Visual Studio 2013 and i keep getting the two following errors

Error C2893 Failed to specialize function template 'unknown-type std::invoke(_Callable &&,_Types &&...)'

and

Error C2672 'std::invoke': no matching overloaded function found

The error is related to file xthread line 238

I am fairly new at c++/MFC and I am trying to write a function that will run in the background to the system time.

This is the code i am using:

void task1(ExperimentTab& dlg)
{
    while (true)
    {
        CString showtime = CTime::GetCurrentTime().Format("%H:%M:%S");
        int x = dlg.m_showTime.GetWindowTextLengthA();
        dlg.m_showTime.SetWindowTextA(_T(""));
        dlg.m_showTime.ReplaceSel(showtime, 0);
    }
}

void mainThread()
{
    std::thread t1(task1);
    t1.join();
}

This is then being called on a button press to start the time, but the same button is used to also stop the time.

Answer 1

Function task1 takes single argument (used as thread body), yet you pass none in t1 constructor. Compiler fails to create std::invoke calling task1 function without method argument.

To fix it call constructor like that: std::thread t1(task1, std::ref(dlg)); , where dlg is ExperimentTab . std::ref ensures that dlg will be passed to thread via reference.

BTW: updating MFC component from other thread might lead to some data races. Also - while(true) thread will consume 100% of CPU by multiple updates per second of timer with second resolution.