HOWTO: Performing Clear Screen (CLS) in a Console Application

ID: Q99261

3.51 4.00 WINDOWS NT

  kbhowto

• Microsoft Win32 Application Programming Interface (API) included with: - Microsoft Windows NT versions 3.51, 4.0 - Microsoft Windows 95

SUMMARY

There is no Win32 application programming interface (API) that will clear the screen in a console application. However, it is fairly easy to write a function that will programmatically clear the screen.

MORE INFORMATION

The following function clears the screen:

 /* Standard error macro for reporting API errors */ 
 #define PERR(bSuccess, api){if(!(bSuccess)) printf("%s:Error %d from %s \ 
    on line %d\n", __FILE__, GetLastError(), api, __LINE__);}

 void cls( HANDLE hConsole )
 {
    COORD coordScreen = { 0, 0 };    /* here's where we'll home the
                                        cursor */ 
    BOOL bSuccess;
    DWORD cCharsWritten;
    CONSOLE_SCREEN_BUFFER_INFO csbi; /* to get buffer info */ 
    DWORD dwConSize;                 /* number of character cells in
                                        the current buffer */ 

    /* get the number of character cells in the current buffer */ 

    bSuccess = GetConsoleScreenBufferInfo( hConsole, &csbi );
    PERR( bSuccess, "GetConsoleScreenBufferInfo" );
    dwConSize = csbi.dwSize.X * csbi.dwSize.Y;

    /* fill the entire screen with blanks */ 

    bSuccess = FillConsoleOutputCharacter( hConsole, (TCHAR) ' ',
       dwConSize, coordScreen, &cCharsWritten );
    PERR( bSuccess, "FillConsoleOutputCharacter" );

    /* get the current text attribute */ 

    bSuccess = GetConsoleScreenBufferInfo( hConsole, &csbi );
    PERR( bSuccess, "ConsoleScreenBufferInfo" );

    /* now set the buffer's attributes accordingly */ 

    bSuccess = FillConsoleOutputAttribute( hConsole, csbi.wAttributes,
       dwConSize, coordScreen, &cCharsWritten );
    PERR( bSuccess, "FillConsoleOutputAttribute" );

    /* put the cursor at (0, 0) */ 

    bSuccess = SetConsoleCursorPosition( hConsole, coordScreen );
    PERR( bSuccess, "SetConsoleCursorPosition" );
    return;
 }

KBCategory:   kbhowto

Keywords          : kbcode kbConsole kbKernBase kbGrpKernBase 
Version           : 3.51 4.00
Platform          : NT WINDOWS

Last Reviewed: May 23, 1998