Passing class method to std::thread, and warning C4573: current default capture mode [duplicate]

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• How to execute a class member function in a separate thread using C++11 thread class? 2 answers

I saw some code like this:

class MyThreadClass
{
public:
  DoThread()
  {
    thread t(&MyThreadClass::ThreadFunc, this);
  }

private:
  ThreadFunc()
  {
    memberVar = 99;
  }

  int memberVar;
};

I'm confused how this works, since ThreadFunc is not passed a this pointer. And when I try to implement it, I get this:

warning C4573: the usage of 'MyThreadClass::memberVar' requires the compiler to capture 'this' but the current default capture mode does not allow it

I don't understand what "default capture mode" is in this context since all my search results turn up questions about lambda functions ([&,this] etc). Is it a compiler switch?