Man Page clog.3

                       Standard C++ Library
             Copyright 1998, Rogue Wave Software, Inc.

NAME

     clog

      - Controls output to a stream buffer  associated  with  the
     object stderr declared in <cstdio>.

SYNOPSIS

     #include <iostream>
     extern ostream clog;
     ostream clog;

DESCRIPTION

     The object clog controls output to a stream  buffer  associ-
     ated  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 manipula-
     tors. See cout or basic_ostream for details.

EXAMPLE

     //
     // 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.

      If your compiler does not support namespaces, then  you  do
      not need the using declaration for std.

SEE ALSO

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

     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