std::isunordered

C++

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abs(int)labsllabsimaxabs (C++11) abs(float)fabs divldivlldivimaxdiv (C++11) fmod	remainder (C++11) remquo (C++11) fma (C++11) fmax (C++11) fmin (C++11) fdim (C++11) nannanfnanl (C++11)(C++11)(C++11)
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erf (C++11) erfc (C++11)	lgamma (C++11) tgamma (C++11)
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ceil floor roundlroundllround (C++11)(C++11)(C++11)	trunc (C++11) nearbyint (C++11) rintlrintllrint (C++11)(C++11)(C++11)
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ldexp scalbnscalbln (C++11)(C++11) ilogb (C++11) logb (C++11)	frexp modf nextafternexttoward (C++11)(C++11) copysign (C++11)
Classification/Comparison
fpclassify (C++11) isfinite (C++11) isinf (C++11) isnan (C++11) isnormal (C++11) signbit (C++11)	isgreater (C++11) isgreaterequal (C++11) isless (C++11) islessequal (C++11) islessgreater (C++11) isunordered (C++11)
Macro constants
HUGE_VALFHUGE_VALHUGE_VALL (C++11)(C++11) INFINITY (C++11) NAN (C++11) math_errhandlingMATH_ERRNOMATH_ERREXCEPT (C++11)	FP_NORMALFP_SUBNORMALFP_ZEROFP_INFINITEFP_NAN (C++11)(C++11)(C++11)(C++11)(C++11)

Defined in header <cmath>
bool isunordered( float x, float y );	(1)	(since C++11)
bool isunordered( double x, double y );	(2)	(since C++11)
bool isunordered( long double x, long double y );	(3)	(since C++11)
bool isunordered( Arithmetic x, Arithmetic y );	(4)	(since C++11)

1-3) 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.

4) A set of overloads or a function template for all combinations of arguments of arithmetic type not covered by (1-3). If any argument has integral type, it is cast to double.

Parameters

x	-	floating point value
y	-	floating point value

Return value

true if either x or y is NaN, false otherwise

See also

fpclassify (C++11)	categorizes the given floating point value (function)
isnan (C++11)	checks if the given number is NaN (function)