Function string_not_empty

example/hyperanf.cc:41–44

DEFINE_uint32(bits,         6,      "hyperloglog bit width used for cardinality estimation");

bool string_not_empty(const char*, const std::string& value) {
  if (0 == value.length()) { return false; }
  return true;
}

DEFINE_validator(input, &string_not_empty);