Listing 2: ConStream.h — interface for the ConStream class

// The ConStream class creates a C++ ostream object that can be 
// used in Win32 C++ programs to write to a console window, often
// for debugging purposes. This code is demonstrated in the 
// ConStreamDemo MFC program, and is fully explained in the 
// accompanying C/C++ Users Journal article. For more details,
// see the article online at http://www.dogma.net/markn
//

//
// This header file defines the entire interface to the ConStream
// class. ConStream is a class that works like a standard
// iostream, and writes to a console window when created in a
// Win32 application. You can only have a single console window
// open at a time, so only a single ConStream object is
// ordinarily created in an application. ConStream is compatible
// with Windows 9x and Windows NT. It uses Unicode text if
// the _UNICODE macro is defined. It must be linked with source
// code found in ConStream.cpp
//
#if !defined( _CONSTREAM_H )
#define _CONSTREAM_H

//
// Note that ConStream uses the standard C++ libraries that ship
// with Visual C++ 5.0 and later, not the older libraries with the
// .h suffix. The library would require some modifications to work
// with the older libraries.
//
#include <iostream>
#include <fstream>


using namespace std;

//
// The ConStream class is derived from what we normally think of
// as ostream, which means you can use standard insertion
// operators to write to it. Of course, this includes insertion
// operators for user defined classes. At all times, a ConStream
// object is either writing out to to a FILE object attached to
// the NUL device, or a FILE object attached to a console
// created using the Win32 API. Which of the two is in use
// depends on whether

// or not the ConStream object has had its Open() or Close()
// method called.
//
class ConStream 
#ifdef _UNICODE
  : public basic_ostream<wchar_t>
#else
  : public basic_ostream<char>
#endif
{
public :
    ConStream();
    virtual ~ConStream();
    void Open();
    void Close();
protected :
    HANDLE m_hConsole;
#ifdef _UNICODE
    basic_filebuf<wchar_t> *m_FileBuf;
    basic_filebuf<wchar_t> m_Nul;      
#else
    basic_filebuf<char> *m_FileBuf;    
    basic_filebuf<char> m_Nul;        
#endif
    FILE *m_fNul;                     
    FILE *m_fConsole;                 
};

#endif // !defined( _CONSTREAM_H )

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