clear

Clears iostate field.

  void clear
     (iostate state = goodbit) throw failure;
  

Use clear() to reset the failbit, eofbit or a badbit that may have been set inadvertently when you wish to override for continuation of your processing. Post-condition of clear is the argument and is equal to rdstate().

If rdstate() and exceptions() != 0 an exception is thrown.

No value is returned.

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

#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) {

   if(count++ == 4) 

   {

      // simulate a failed state

      in.setstate(ios::failbit);

      in.clear();

   }

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