Please a real simple Visual Studio C and C++ prof solution to avoid conio.h in W10 and input from console without waiting/return?

Question

I can nowhere find a simple (!), no tweaking, as much as possible standard C / C++ implementation in Windows Visual Studio of the old getkey() function that does not wait, but immediately responses with either the read character or a NILL/EOF code. Something like this [working under conio]:

if (_kbhit())
    { 
        ch = _getch();

        return(ch);
    }
 else
    {
        return(Nill); // or EOF or something like that
    }

Answer 1

The idea of the following sample is to use a wait function to see if there is console input. If there is input then the code looks for a key up record and returns the character value. Input records in the buffer that are not KEY_EVENT records are ignored. If the buffer is empty (or only contains events that are not KEY_EVENT records) the code returns EOF.

int GetChNoWait()
{
    INPUT_RECORD rec;
    HANDLE hInput = NULL;

    hInput = GetStdHandle(STD_INPUT_HANDLE);
    while (WaitForSingleObject(hInput, 0) == WAIT_OBJECT_0)
    {
        DWORD dwRead;
        ReadConsoleInput(hInput, &rec, 1, &dwRead);
        if (rec.EventType != KEY_EVENT)
            continue;
        else if(rec.Event.KeyEvent.bKeyDown)
            continue;
        else
        {
        #ifdef UNICODE
            return (int) rec.Event.KeyEvent.uChar.UnicodeChar;
        #else
            return (int) rec.Event.KeyEvent.uChar.AsciiChar;
        #endif
        }
    }

    return EOF;
}

Answer 2

Hello @Jan van der Zanden

Straight to the point, have you tried:

fflush(stdin);  
getchar();  

Hope this helps,
Best regards,

Answer 3

I have this MS function in archives (I just tested, it does the same thing as _getch()) :

WCHAR myGetchar(void)
{
    HANDLE hStdIn; /* standard input */
    DWORD dwInputMode; /* to save the input mode */
    BOOL bSuccess;
    WCHAR chBuf; /* buffer to read into */
    DWORD dwRead;
    /* get the standard input handle to read from. There is only one */
    /* instance of standard input per process at any given time */
    hStdIn = GetStdHandle(STD_INPUT_HANDLE);
    /* save the console mode */
    bSuccess = GetConsoleMode(hStdIn, &dwInputMode);
    /* disable line input. Echo input must be disabled when disabling */
    /* line input */
    bSuccess = SetConsoleMode(hStdIn, dwInputMode & ~ENABLE_LINE_INPUT & ~ENABLE_ECHO_INPUT);
    /* read a character from the console input */
    bSuccess = ReadFile (hStdIn, &chBuf, sizeof(chBuf), &dwRead, NULL);
    /* restore the original console input mode */
    bSuccess = SetConsoleMode(hStdIn, dwInputMode);
    return(chBuf);
}

Answer 4

I will try both answers. Thanks!!!