Standard C++ LibraryCopyright 1996, Rogue Wave Software, Inc.

NAME

  clog

SYNOPSIS

  #include <iostream>
  extern ostream clog;

DESCRIPTION

  ostream clog;
     The object clog controls output to a stream buffer associated with the
     object stderr declared in <cstdio>. The difference between clog and cerr
     is that clog is buffered but cerr is not. Therefore, commands like clog
     << "ERROR !!"; and fprintf(stderr,"ERROR !!"); are not synchronized.

FORMATTING

  The formatting is done through member functions or manipulators.  See cout
  or basic_ostream for details.

EXAMPLES

  //
  // clog example
  //
  #include<iostream>
  #include<fstream>

  void main ( )
  {
   using namespace std;

    // open the file "file_name.txt"
    // for reading
   ifstream in("file_name.txt");

    // output the all file to stdout
   if ( in )
     cout << in.rdbuf();
   else
      // if the ifstream object is in a bad state
      // output an error message to stderr
     clog << "Error while opening the file" << endl;
  }

WARNINGS

  clog can be used to redirect some of the errors to another recipient. For
  example, you might want to redirect them to a file named my_err:

  ofstream out("my_err");

  if ( out )
   clog.rdbuf(out.rdbuf());

  else

   cerr << "Error while opening the file" << endl;

  Then when you are doing something like clog << "error number x"; the error
  message is output to the file my_err. Obviously, you can use the same
  scheme to redirect clog to other devices.

SEE ALSO

  basic_ostream(3C++std), iostream(3C++std), basic_filebuf(3C++std),
  cout(3C++std), cin(3C++std), cerr(3C++std), wcin(3C++std), wcout(3C++std),
  wcerr(3C++std), wclog(3C++std), iomanip(3C++std), ios_base(3C++std),
  basic_ios(3C++std),

  Working Paper for Draft Proposed International Standard for Information
  Systems--Programming Language C++, Section 27.3.1

STANDARDS CONFORMANCE

  ANSI X3J16/ISO WG21 Joint C++ Committee



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