How should I use "-fork" option in mclInitializeApplication in R2019b?

Hi,

I saw the documents here: https://www.mathworks.com/help/compiler_sdk/cxx/mclinitializeapplication.html?searchHighlight=mclInitializeApplication&s_tid=doc_srchtitle showing that we can use option "-fork" for mclInitializeApplication when initialize a Matlab Runtime Instance in R2019b but I cannot find any furthur explaination regarding this option.

And when I tried to use following code to initialize the mcr:

const char* mcr_options[] = {"-fork"};
  if (!mclInitializeApplication(mcr_options, 1)) {
    std::cerr << "Could not initialize the application properly" << std::endl;
    return -1;
  } else {
    std::cout << "Done mclInitializeApplication" << std::endl;
  }

I keep receive this warning: "Warning: Unrecognized command line option: fork."

I wonder if this option is truely implemented inside R2019b. If so, how can I make it work properly?

Thanks