isunordered

From cppreference.com
< c‎ | numeric‎ | math
 
 
 
Common mathematical functions
Functions
Basic operations
(C99)
(C99)
(C99)
(C99)
(C99)
(C99)(C99)(C99)
Exponential functions
(C99)
(C99)
(C99)
(C99)
Power functions
(C99)
(C99)
Trigonometric and hyperbolic functions
(C99)
(C99)
(C99)
Error and gamma functions
(C99)
(C99)
(C99)
(C99)
Nearest integer floating point operations
(C99)(C99)(C99)
(C99)
(C99)(C99)(C99)
Floating point manipulation functions
(C99)(C99)
(C99)
(C99)
Classification
(C99)
(C99)
(C99)
(C99)
isunordered
(C99)
Types
(C99)(C99)
Macro constants
 
Defined in header <math.h>
#define isunordered(x, y) /* implementation defined */
(since C99)

Determines if the floating point numbers x and y are unordered, that is, one or both are NaN and thus cannot be meaningfully compared with each other.

Parameters

x - floating point value
y - floating point value

Return value

Nonzero integral value if either x or y is NaN, 0 otherwise.