std::numeric_limits::denorm_min

 

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numeric_limits::denorm_min

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float_round_style

float_denorm_style

 

static T denorm_min();		(until C++11)
static constexpr T denorm_min();		(since C++11)

Returns the minimum positive subnormal value of the type T, if std::numeric_limits<T>::has_denorm != std::denorm_absent, otherwise returns std::numeric_limits<T>::min(). Only meaningful for floating-point types.

Return value

T	std::numeric_limits<T>::denorm_min()
/* non-specialized */	T();
bool	false
char	​0​
signed char	​0​
unsigned char	​0​
wchar_t	​0​
char16_t	​0​
char32_t	​0​
short	​0​
unsigned short	​0​
int	​0​
unsigned int	​0​
long	​0​
unsigned long	​0​
long long	​0​
unsigned long long	​0​
float	2-149 if std::numeric_limits<float>::is_iec559 == true
double	2-1074 if std::numeric_limits<double>::is_iec559 == true
long double	/* implementation-defined */

Exceptions

(none)	(until C++11)
noexcept specification:   noexcept	(since C++11)

Example

Demonstates the underlying bit structure of the denorm_min()

Run this code

#include <cstdint>
#include <limits>
#include <cassert>
int main()
{
    // the smallest subnormal value has sign bit = 0, exponent = 0
    // and only the least significant bit of the fraction is 1
    uint32_t denorm_bits = 0x0001;
    float denorm_float = reinterpret_cast<float&>(denorm_bits);
    assert(denorm_float == std::numeric_limits<float>::denorm_min());
}

See also

min [static]	returns the smallest finite value of the given type (public static member function)
has_denorm [static]	identifies the denormalization style used by the floating-point type (public static member constant)
lowest [static] (C++11)	returns the lowest finite value of the given type (public static member function)