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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 subsequent
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 operation, or the
maximum representable value of std::streamsize if the number is not representable.

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 retroactively to
previously published C++ standards.


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

2024.06.10 http://cppreference.com