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std::numeri...::denorm_min(3)  C++ Standard Libary std::numeri...::denorm_min(3)

NAME
     std::numeric_limits::denorm_min - std::numeric_limits::denorm_min

Synopsis
	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 re-
     turns
	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>::de-
     norm_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      0
	C++11)
					     FLT_TRUE_MIN	  (\(\scriptsize
     2^{-149}\)2-149
	float				     if
					     std::numeric_lim-
     its<float>::is_iec559 is true)
					     DBL_TRUE_MIN	  (\(\scriptsize
     2^{-1074}\)2-1074
	double				     if
					     std::numeric_limits<dou-
     ble>::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		 returns the smallest finite value of the given type
	[static]	 (public static member function)
	has_denorm	 identifies the denormalization style used by the float-
     ing-point
	[static]	 type
			 (public static member constant)
	lowest		 returns the lowest finite value of the given type
	[static] (C++11) (public static member function)

http://cppreference.com 	   2024.06.10	   std::numeri...::denorm_min(3)
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