Best way to check if double equals negative infinity in C++

Question

I found this: http://en.cppreference.com/w/cpp/numeric/math/isinf but it appears to check for either positive or negative infinity. I just want to check if a value is equal

Answer 1

How about the obvious and explicit?

To check that a double x is negative infinity, check

x == -std::numeric_limits::infinity()

If x is some other floating-point type, change double as appropriate.

std::numeric_limits is defined in the standard header . Don't forget to add it to your #include list.