[OCLUG-Tech] why does g++ not issue a narrowing error?

["Robert P. J. Day" <rpjday [ at ] crashcourse [ dot ] ca>]

  currently rewriting my C++ courses from some time back, and wanted
to demonstrate a simply narrowing error; to wit:

int
main()
{
        bool b1 {true};
        bool b2 {false};
        bool b3 {7};    // narrowing error?

        int i {42};
        int j {42.1};   // narrowing error?
}

  oddly, if i use "clang -std=c++11 narrow.cpp", both of those
narrowing conversions are flagged, but if i use "g++ -std=c++11
narrow.cpp", only the second is flagged -- g++ seems fine with
narrowing an int to a bool, even though stroustrup's book on C++11
clearly suggests that should be an error as long as one uses C++ style
curly brace initialization:

  bool b1 = 7; // 7!=0, so b becomes true
  bool b2 {7}; // error : narrowing (§2.2.2, §10.5)

any C++ wizards out there want to comment on this?

rday