NAME¶

std::isnormal - std::isnormal

Synopsis¶

Defined in header <cmath>
bool isnormal( float num );
(since C++11)
bool isnormal( double num ); (until C++23)

bool isnormal( long double num );
constexpr bool isnormal( /* floating-point-type */ (1) (since C++23)
num );
Additional overloads
Defined in header <cmath>
template< class Integer > (A) (since C++11)
bool isnormal( Integer num ); (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)
A) Additional overloads are provided for all integer types, which are treated as
double.

Parameters¶

num - floating-point or integer value

Return value¶

true if num is normal, false otherwise.

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