lambda pointer capture

#include <cstdio>

int main()
{
  auto a = []() { return new char; };
  char* b = a();
  std::printf("%p\n", b); // -> "0x..."
  auto c = [b]() { std::printf("%p\n", b); };
  c(); // -> "0x..."
  auto d = [&b]() { delete b; b = NULL; };
  d();
  std::printf("%p\n", b); // -> "(nil)"
}