bad

To test for fatal I/O error.

  bool bad() const
  

Use the member function bad() to test if a fatal input or output error occurred which sets the badbit flag in the stream.

Returns true if badbit is set in rdstate().

basic_ios::fail()

// The file ewl-test contains:
// abcdefghijklmnopqrstuvwxyz

#include <iostream>

#include <fstream>

#include <cstdlib>

char * inFile = "ewl-test";

using namespace std;

void status(ifstream &in);

int main()

{

   ifstream in(inFile);

   if(!in.is_open()) 

   {

      cout << "could not open file for input";

      exit(1);

   }

   int count = 0;

   int c;

   while((c = in.get()) != EOF) 

   {

      // simulate a failed state

      if(count++ == 4) in.setstate(ios::failbit);

      status(in);

   }

   status(in);

   in.close();

   return 0;

}

void status(ifstream &in)

{

      // note: eof() is not needed in this example 

      // if(in.eof()) cout << "EOF encountered \n";

   if(in.fail()) cout << "Non-Fatal I/O Error \n";

   if(in.good()) cout << "GoodBit set \n";    

   if(in.bad()) cout << "Fatal I/O Error \n";

}

Result:

  GoodBit set 
  GoodBit set 
  GoodBit set 
  GoodBit set 
  Non-Fatal I/O Error 
  Non-Fatal I/O Error