Why do I get “warning: missing initializer for member”? [-Wmissing-field-initializers]

Question

I\'m wondering why I am getting a warning about initialization in one case, but not the other. The code is in a C++ source file, and using GCC 4.7 with -std=c++11

Answer 1

Here is a simple example:

#include 

struct S {
  int a;
  int b;
};

int main() {
  S s { 1 }; // b will be automatically set to 0
             // and that's probably(?) not what you want
  std::cout<<"s.a = "<