std::isnormal

 

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Defined in header <cmath>
	(1)
bool isnormal( float num ); bool isnormal( double num ); bool isnormal( long double num );			(since C++11) (until C++23)
constexpr bool isnormal( /*floating-point-type*/ num );			(since C++23)
SIMD overload (since C++26)
Defined in header <simd>
template< /*math-floating-point*/ V > constexpr typename /*deduced-simd-t*/<V>::mask_type   isnormal ( const V& v_num );		(S)	(since C++26)
Additional overloads
Defined in header <cmath>
template< class Integer > bool isnormal( Integer num );		(A)	(since C++11) (constexpr since C++23)

1) Determines if the given floating point number num is normal, i.e. is neither zero, subnormal, infinite, nor NaN. The library provides overloads for all cv-unqualified floating-point types as the type of the parameter num.(since C++23)

S) The SIMD overload performs an element-wise std::isnormal on v_num. (See math-floating-point and deduced-simd-t for their definitions.)

(since C++26)

A) Additional overloads are provided for all integer types, which are treated as double.

Parameters

num	-	floating-point or integer value
v_num	-	a data-parallel object of std::basic_simd specialization where its element type is a floating-point type

Return value

1) true if num is normal, false otherwise.

S) A data-parallel mask object where the i^th element equals true if v_num[i] is normal or false otherwise for all i in the range [​0​, v_num.size()).

Notes

The additional overloads are not required to be provided exactly as (A). They only need to be sufficient to ensure that for their argument num of integer type, std::isnormal(num) has the same effect as std::isnormal(static_cast<double>(num)).

Example

Run this code

#include <cfloat>
#include <cmath>
#include <iostream>
 
int main()
{
    std::cout << std::boolalpha
              << "isnormal(NaN) = " << std::isnormal(NAN) << '\n'
              << "isnormal(Inf) = " << std::isnormal(INFINITY) << '\n'
              << "isnormal(0.0) = " << std::isnormal(0.0) << '\n'
              << "isnormal(DBL_MIN/2.0) = " << std::isnormal(DBL_MIN / 2.0) << '\n'
              << "isnormal(1.0) = " << std::isnormal(1.0) << '\n';
}

Output:

isnormal(NaN) = false
isnormal(Inf) = false
isnormal(0.0) = false
isnormal(DBL_MIN/2.0) = false
isnormal(1.0) = true

See also

fpclassify (C++11)	categorizes the given floating-point value (function)
isfinite (C++11)	checks if the given number has finite value (function)
isinf (C++11)	checks if the given number is infinite (function)
isnan (C++11)	checks if the given number is NaN (function)
C documentation for isnormal