std::numeric_limits<T>::denorm_min

static T denorm_min() throw();		(until C++11)
static constexpr T denorm_min() noexcept;		(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`
`char8_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 */

Example

Demonstates the underlying bit structure of the denorm_min() and prints the values.

#include <cassert>
#include <cstdint>
#include <cstring>
#include <iostream>
#include <limits>
 
int main()
{
    // the smallest subnormal value has sign bit = 0, exponent = 0
    // and only the least significant bit of the fraction is 1
    std::uint32_t denorm_bits = 0x0001;
    float denorm_float;
    std::memcpy(&denorm_float, &denorm_bits, sizeof(float));
 
    assert(denorm_float == std::numeric_limits<float>::denorm_min());
 
    std::cout << "float\tmin()\t\tdenorm_min()\n";
    std::cout << "\t" << std::numeric_limits<float>::min() << '\t';
    std::cout <<         std::numeric_limits<float>::denorm_min() << '\n';
 
    std::cout << "double\tmin()\t\tdenorm_min()\n";
    std::cout << "\t" << std::numeric_limits<double>::min() << '\t';
    std::cout <<         std::numeric_limits<double>::denorm_min() << '\n';
}

Possible output:

float        min()                denorm_min()
        1.17549e-38        1.4013e-45
double        min()                denorm_min()
        2.22507e-308        4.94066e-324

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)

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std::numeric_limits<T>::denorm_min

Return value

Example

See also