# std::numeric_limits<T>::denorm_min

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< cpp‎ | types‎ | numeric limits

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 if std::numeric_limits<float>::is_iec559 is true)
double | DBL_TRUE_MIN (\(\scriptsize 2^{-1074}\)2-1074 if std::numeric_limits<double>::is_iec559 is true)
long double | LDBL_TRUE_MIN

### Example

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

Run this code

    #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

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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