std::numeric_limits<T>::denorm_min - cppreference.com
From cppreference.com
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(until C++11) | |
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(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
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std::numeric_limits<T>::denorm_min()
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/* non-specialized */
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T()
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bool
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false
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char
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0
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signed char
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0
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unsigned char
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0
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wchar_t
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0
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char8_t (since C++20)
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0
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char16_t (since C++11)
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0
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char32_t (since C++11)
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0
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short
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0
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unsigned short
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0
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int
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0
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unsigned int
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0
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long
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0
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unsigned long
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0
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long long (since C++11)
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0
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unsigned long long since (since C++11)
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0
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float
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FLT_TRUE_MIN (2-149 if std::numeric_limits<float>::is_iec559 is true)
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double
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DBL_TRUE_MIN (2-1074 if std::numeric_limits<double>::is_iec559 is true)
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long double
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LDBL_TRUE_MIN |
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
See also
| returns the smallest finite value of the given non-floating-point type, or the smallest positive normal value of the given floating-point type (public static member function) [edit] | |
| identifies the denormalization style used by the floating-point type (public static member constant) [edit] | |
returns the lowest finite value of the given type, i.e. the most negative value for signed types, 0 for unsigned types (public static member function) [edit] |