HUGE_VALF, HUGE_VAL, HUGE_VALL
From cppreference.com
                    
                                        
                    
                    
                                                            
                    |   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 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.
See also
|    (C++11)  | 
   evaluates to positive infinity or the value guaranteed to overflow a float  (macro constant)  |