using stdout in GUI programs

gistfile1.c

/**
 * The following function shows one way that a GUI application can redirect the stdout 
 * stream to a new console    window. After the following function has been called, the 
 * GUI program can use C runtime functions like printf to display information on the 
 * console window. This can be useful during debugging.
 */

 

// Version 1:
 

void RedirectStdOut(void)
{
    CONSOLE_SCREEN_BUFFER_INFO csbi;

    // Create a new console window.
    if (!AllocConsole()) return;

    // Set the screen buffer to be larger than normal (this is optional).
    if (GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &csbi))
    {
        csbi.dwSize.Y = 1000; // any useful number of lines...
        SetConsoleScreenBufferSize(GetStdHandle(STD_OUTPUT_HANDLE), csbi.dwSize);
    }

    // Redirect "stdout" to the console window.
    fclose(stdout);
    setbuf(stdout, NULL);
    *stdout = *_fdopen(_open_osfhandle((long)GetStdHandle(STD_OUTPUT_HANDLE), 0), "w");
}


 
// Version 2:
 

void RedirectStdOut(void)
{
    CONSOLE_SCREEN_BUFFER_INFO csbi;

    // Create a new console window.
    if (!AllocConsole()) return;

    // Set the screen buffer to be larger than normal (this is optional).
    if (GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &csbi))
    {
        csbi.dwSize.Y = 1000; // any useful number of lines...
        SetConsoleScreenBufferSize(GetStdHandle(STD_OUTPUT_HANDLE), csbi.dwSize);
    }
 

    // Redirect "stdin" to the console window.
    if (!freopen("CONIN$", "w", stdin)) return;
 

    // Redirect "stderr" to the console window.
    if (!freopen("CONOUT$", "w", stderr)) return;

    // Redirect "stdout" to the console window.
    if (!freopen("CONOUT$", "w", stdout)) return;
 

    // Turn off buffering for "stdout" ("stderr" is unbuffered by default).

    setbuf(stdout, NULL);
}

Hi,
It seems that first version doesn't work with VS2015, at least "*stdout = " line has no effect.
FILE struct, and stdin/stdout/stderr have been redefined in VS2015
2nd version still works, thanks ;)
Regards.

The second version is incorrect, because it obliterates the distinction between stdout and stderr. For instance, you will not be able to have stdout redirected to a file and at the same time have stderr writing to the console window. The version with _open_osfhandle does maintain the distinction between stdout and stderr.