HUGE_VALF, HUGE_VAL, HUGE_VALL

Defined in header <cmath>
#define HUGE_VALF /* implementation defined */		(since C++11)
#define HUGE_VAL  /* implementation defined */
#define HUGE_VALL /* implementation defined */		(since C++11)

The macros HUGE_VALF , HUGE_VAL and HUGE_VALL macros expand to positive floating point constant expressions which compare equal to the values returned by floating-point functions and operators in case of overflow (see math_errhandling ).

Constant	Explanation
HUGE_VALF	Expands to positive float expression that indicates overflow
HUGE_VAL	Expands to positive double expression that indicates overflow, not necessarily representable as a float
HUGE_VALL	Expands to positive long double expression that indicates overflow, not necessarily representable as a float or double

On implementations that support floating-point infinities, these macros always expand to the positive infinities of float , double , and long double , respectively.

Notes

On implementations that do not support floating-point infinities, these macros expand to the maximum finite number of their respective types.

C++98 added float and long double overloads of mathematical functions. There is a problem that the float overloads cannot return HUGE_VAL to indicate overflow because this macro is not guaranteed to be representable as a float .

LWG issue 357 was raised to target this problem. LWG found that C99 has the same problem ( float and long double overloads were also added in C99), and C99 introduced new macros HUGE_VALF and HUGE_VALL to solve the problem. Therefore the issue was closed and the C99 resolution was adopted in C++11.

See also

INFINITY (C++11)	evaluates to positive infinity or the value guaranteed to overflow a float (macro constant)
C documentation for HUGE_VAL