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() for floating point types and T() for all other types. 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 (since C++20) ​0​
char16_t (since C++11) ​0​
char32_t (since C++11) ​0​
short ​0​
unsigned short ​0​
int ​0​
unsigned int ​0​
long ​0​
unsigned long ​0​
long long (since C++11) ​0​
unsigned long long since (since C++11) ​0​
float FLT_TRUE_MIN (\(\scriptsize 2^{-149}\)2-149
std::numeric_limits<float>::is_iec559 is true)
double DBL_TRUE_MIN (\(\scriptsize 2^{-1074}\)2-1074
std::numeric_limits<double>::is_iec559 is true)
long double LDBL_TRUE_MIN


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

See also

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

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