std::basic_ios<CharT,Traits>:: eof

Returns true if the associated stream has reached end-of-file. Specifically, returns true if eofbit is set in rdstate() .

See ios_base::iostate for the list of conditions that set eofbit .

Parameters

(none)

Return value

true if an end-of-file has occurred, false otherwise.

Notes

This function only reports the stream state as set by the most recent I/O operation; it does not examine the associated data source. For example, if the most recent I/O was a get() which returned the last byte of a file, eof() returns false . The next get() fails to read anything and sets the eofbit . Only then does eof() return true .

In typical usage, input stream processing stops on any error. eof() and fail() can then be used to distinguish between different error conditions.

Example

#include <cstdlib>
#include <fstream>
#include <iostream>
 
int main()
{
    std::ifstream file("test.txt");
    if (!file) // operator! is used here
    {  
        std::cout << "File opening failed\n";
        return EXIT_FAILURE;
    }
 
    // typical C++ I/O loop uses the return value of the I/O function
    // as the loop controlling condition, operator bool() is used here
    for (int n; file >> n;)
       std::cout << n << ' ';
    std::cout << '\n';
 
    if (file.bad())
        std::cout << "I/O error while reading\n";
    else if (file.eof())
        std::cout << "End of file reached successfully\n";
    else if (file.fail())
        std::cout << "Non-integer data encountered\n";
}

See also

The following table shows the value of basic_ios accessors ( good() , fail() , etc.) for all possible combinations of ios_base::iostate flags: