isinf
From cppreference.com
                    
                                        
                    
                    
                                                            
                    |   Defined in header  
<math.h>
  | 
||
|   #define isinf(arg) /* implementation defined */ 
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(since C99) | |
Determines if the given floating point number arg is positive or negative infinity. The macro returns an integral value.
[edit] Parameters
| arg | - | floating point value | 
[edit] Return value
Nonzero integral value if arg is infinite, 0 otherwise.
[edit] See also
|    (C99) 
 | 
   categorizes the given floating point value   (function)  | 
|    (C99) 
 | 
   checks if the given number has finite value   (function)  | 
|    (C99) 
 | 
   checks if the given number is NaN  (function)  | 
|    (C99) 
 | 
   checks if the given number is normal   (function)  |