Why does std::numeric_limits::max() return 0?

Question

I found an interesting gotcha with std::numeric_limits::max() returning 0. The answer is to use seconds::max() or std::numeric_lim

Answer 1

std::numeric_limits is not specialized for std::chrono::seconds. Default definitions are given for all data members and functions in std::numeric_limits to avoid compiler errors for unspecialized types. The default version of numeric_limits::max() simply returns T(), which is 0 in this case.

You can check if std::numeric_limits is specialized for a given T at compile time by checking std::numeric_limits::is_specialized, which defaults to false.