minimum double value in C/C++

Question

Is there a standard and/or portable way to represent the smallest negative value (e.g. to use negative infinity) in a C(++) program?

DBL_MIN in float.h is the smalle

Answer 1

Are you looking for actual infinity or the minimal finite value? If the former, use

-numeric_limits::infinity()

which only works if

numeric_limits::has_infinity

Otherwise, you should use

numeric_limits::lowest()

which was introduces in C++11.

If lowest() is not available, you can fall back to

-numeric_limits::max()

which may differ from lowest() in principle, but normally doesn't in practice.