Reference
C Library
IOstream Library
Strings library
STL Containers
STL Algorithms
Miscellaneous
IOstream Library
manipulators
classes:
filebuf
fstream
ifstream
ios
iostream
ios_base
istream
istringstream
ofstream
ostream
ostringstream
streambuf
stringbuf
stringstream
objects:
cerr
cin
clog
cout
types:
fpos
streamoff
streampos
streamsize
ios
ios::ios
ios::~ios
member functions:
ios::bad
ios::clear
ios::copyfmt
ios::eof
ios::exceptions
ios::fail
ios::fill
ios::good
ios::imbue
ios::init
ios::narrow
ios::operator!
ios::operator void*
ios::rdbuf
ios::rdstate
ios::setstate
ios::tie
ios::widen


ios::operator!

public member function
bool operator ! ( ) const;

Evaluate stream object

Returns true if either one of the error flags (failbit or badbit) is set on the stream. Otherwise it returns false.

This behavior is equivalent to the member function fail().

Parameters

none

Return Value

true if either failbit or badbit is set.
false otherwise.

Example

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// evaluating a stream object
#include <iostream>
#include <fstream>
using namespace std;
int main () {
  ifstream is;
  is.open ("test.txt");
  if (!is)
    cerr << "Error opening 'test.txt'\n";
  return 0;
}


Basic template member declaration

( basic_ios<charT,traits> )
  
bool operator ! () const;


See also

ios::fail Check if either failbit or badbit is set (public member function)
ios::good Check if the state of the stream is good for i/o operations. (public member function)