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std::basic_istream::gcount(3)  C++ Standard Libary std::basic_istream::gcount(3)

NAME
     std::basic_istream::gcount - std::basic_istream::gcount

Synopsis
	std::streamsize gcount() const;

	Returns the number of characters extracted by the last unformatted input
     operation,
	or  the  maximum representable value of std::streamsize if the number is
     not
	representable.

	The following member functions of basic_istream change the value of sub-
     sequent
	gcount() calls:

	  * move constructor
	  * swap()
	  * get()
	  * getline()
	  * ignore()
	  * read()
	  * readsome()
	  * operator>>(basic_streambuf*)

	The following functions set gcount() to zero:

	  * constructor
	  * putback()
	  * unget()
	  * peek()

Parameters
	(none)

Return value
	The number of characters extracted by the last unformatted input  opera-
     tion, or the
	maximum representable value of std::streamsize if the number is not rep-
     resentable.

Example
     // Run this code

      #include <iostream>
      #include <sstream>

      int main()
      {
	  char x[20];
	  std::istringstream stream("Hello World");

	  stream.read(x, sizeof x);
	  std::cout << "Characters extracted: " << stream.gcount();
      }

Output:
      Characters extracted: 11

	Defect reports

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

	   DR	 Applied to	       Behavior as  published		    Cor-
     rect behavior
	LWG 3464 C++98	    the return value was unspecified when the	 returns
     the maximum
			    result overflows				 value

http://cppreference.com 	   2024.06.10	   std::basic_istream::gcount(3)
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