- declareFlag(name, description, value, [&value, callback](const T& val) {
- if (not callback(val))
- throw std::range_error("invalid value");
- value = std::move(val);
- });
+ declareFlag(name, description, value,
+ std::function<void(const T&)>([&value, callback](const T& val) {
+ if (not callback(val))
+ throw std::range_error("invalid value");
+ value = std::move(val);
+ })
+ );