Question

I’m having a problem with _beginthread in microsoft visual studio c++ 10 express:
my code:

void __cdecl DashThread( void * Args ) // function without any class refs
{
    while(1){
        MessageBox::Show("work");
        Sleep(5000);
    }
    _endthread();
}

private:
    System::Void button8_Click_1(System::Object^  sender, System::EventArgs^  e) {
        HANDLE HDash = ( HANDLE ) _beginthread(DashThread, 0, NULL );
    }

and errors:

error C3641: ‘DashThread’ : invalid calling convention ‘__cdecl ‘ for function compiled with /clr:pure or /clr:safe

error C2664: ‘beginthread’ : cannot convert parameter 1 from ‘void (_cdecl *)(void *)’ to ‘void (__cdecl *)(void *)’

Answer 1

From the compiler error it seems you are compiling your project with /clr:pure or /clr:safe (in which case you are not programming in C++, but C++/CLI by the way) and thus cannot use the __cdecl calling convention, which is in turn required by _beginthread.

If you are programming in C++/CLI (and thus .NET) anyway, then why not just use .NET’s threading facilities instead of the strange pseudo-standard-Win32-wrapper _beginthread?

If you want to use C++/CLI, but still be able to use good old _beginthread, then try to compile it with just /clr instead of /clr:pure, which allows non-managed functions that can have __cdecl calling convention.