std::basic_istream<CharT,Traits>::gcount

From cppreference.com
< cpp‎ | io‎ | basic istream
 
 
 
 
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:

The following functions set gcount() to zero:

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

#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 result overflows returns the maximum value