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std::iostream_category(3)      C++ Standard Libary     std::iostream_category(3)

NAME
     std::iostream_category - std::iostream_category

Synopsis
	Defined in header <ios>
	const std::error_category& iostream_category() noexcept;  (since C++11)

	Obtains a reference to the static error category object for iostream er-
     rors. The
	object	 is  required  to  override  the  virtual  function  error_cate-
     gory::name() to return
	a pointer to the string "iostream". It is used to identify  error  codes
     provided in
	the exceptions of type std::ios_base::failure.

Parameters
	(none)

Return value
	A  reference  to  the static object of unspecified runtime type, derived
     from
	std::error_category.

Example
     // Run this code

      #include <fstream>
      #include <iostream>

      int main()
      {
	  std::ifstream f("doesn't exist");
	  try
	  {
	      f.exceptions(f.failbit);
	  }
	  catch (const std::ios_base::failure& e)
	  {
	      std::cout << "Caught an ios_base::failure.\n"
			<< "Error code: " << e.code().value()
			<< " (" << e.code().message() << ")\n"
			<< "Error category: " <<  e.code().category().name()  <<
     '\n';

	  }
      }

Possible output:
      Caught an ios_base::failure.
      Error code: 1 (unspecified iostream_category error)
      Error category: iostream

	Defect reports

	The  following	behavior-changing  defect  reports were applied retroac-
     tively to
	previously published C++ standards.

	   DR	 Applied to	       Behavior as published		 Correct
     behavior
	LWG 2087 C++11	    iostream_category was not declared noexcept declared
     noexcept

See also
	failure stream exception
		(public member class of std::ios_base)
	io_errc the IO stream error codes
	(C++11) (enum)

http://cppreference.com 	   2024.06.10	       std::iostream_category(3)
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