How do you check for infinite and indeterminate values in C++?

Question

In my programs infinity usually arises when a value is divided by zero. I get indeterminate when I divide zero by zero. How do you check for infinite and indeterminate value

Answer 1

Although C++03 doesn't provide C99's isnan and isinf macros, C++11 standardizes them by providing them as functions. If you can use C++11, instead of strict C++03, then these would be cleaner options, by avoiding macros, compiler built-ins and platform-dependant functions.

C++11's std::isfinite returns true for all values except inf and nan; so !isfinite should check for infinite and indeterminate values in one shot.