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