std::numeric_limits<T>::denorm_min

Since C++11

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

# Declarations

static T denorm_min() throw();

(until C++11)

static constexpr T denorm_min() noexcept;

(since C++11)

# Example

#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';
}

# See also