Windows read console non-blocking

read_console.c

#include <stdio.h>
#include <Windows.h>

COORD GetConsoleCursorPosition(HANDLE hConsoleOutput)
{
    CONSOLE_SCREEN_BUFFER_INFO cbsi;
    if (GetConsoleScreenBufferInfo(hConsoleOutput, &cbsi))
    {
        return cbsi.dwCursorPosition;
    }
    else
    {
        // The function failed. Call GetLastError() for details.
        COORD invalid = { 0, 0 };
        return invalid;
    }
}

int main(int argc, char** argv){
    printf("Hello, from term!\n");

    HANDLE hStdIn = GetStdHandle(STD_INPUT_HANDLE);
    HANDLE hStdOut = GetStdHandle(STD_OUTPUT_HANDLE);

    DWORD dwMode;
    GetConsoleMode(hStdIn, &dwMode);
    // It seems both is ok under VSCode integrated terminal. But not work for other terminal.
    // dwMode = ENABLE_WINDOW_INPUT | ENABLE_PROCESSED_INPUT;
    dwMode &= ~(ENABLE_ECHO_INPUT | ENABLE_LINE_INPUT);
    printf("Mode: %d\t%x\n", dwMode, dwMode);
    if(!SetConsoleMode(hStdIn, dwMode)) {
        return -1;
    }
    FlushConsoleInputBuffer(hStdIn);

    char buff[128];
    DWORD dwRead = 0;
    DWORD dwWritten;
    BOOL timeout = FALSE;
    while(TRUE) {

        DWORD dwRet = WaitForSingleObject(hStdIn, 1000);
        switch(dwRet) {
        case WAIT_OBJECT_0:
            ReadFile(hStdIn, buff, 128, &dwRead, NULL);
            WriteFile(hStdOut, buff, dwRead, &dwWritten, NULL);
            if (dwRead == 1) {
                if (buff[0] == '\r') {
                    COORD coord = GetConsoleCursorPosition(hStdOut);
                    CONSOLE_SCREEN_BUFFER_INFO screen;
                    GetConsoleScreenBufferInfo(hStdOut, &screen);
                    DWORD size = screen.srWindow.Right;
                    for (int i = screen.srWindow.Left; i < screen.srWindow.Right; ++i) {
                        WriteFile(hStdOut, " ", 1, NULL, NULL);
                    }
                    SetConsoleCursorPosition(hStdOut, coord);
                }
            }
            break;
        case WAIT_TIMEOUT:
            // printf("2");
            timeout = TRUE;
            break;
        default:
            break;
        }

        COORD coord = GetConsoleCursorPosition(hStdOut);
        COORD newCoord = coord;
        newCoord.Y += 2;
        newCoord.X = 0;
        // clear the line;
        SetConsoleCursorPosition(hStdOut, newCoord);
        CONSOLE_SCREEN_BUFFER_INFO screen;
        GetConsoleScreenBufferInfo(hStdOut, &screen);
        DWORD size = screen.srWindow.Right;
        for (int i = screen.srWindow.Left; i < screen.srWindow.Right; ++i) {
            WriteFile(hStdOut, " ", 1, NULL, NULL);
        }
        buff[dwRead] = '\0';
        // write content
        SetConsoleCursorPosition(hStdOut, newCoord);
        if (timeout) {
            printf("Timeout");
        } else {
            printf("Read char count: %d, buff:%s", dwRead, buff);
        }
        SetConsoleCursorPosition(hStdOut, coord);
        dwRead = 0;
        ZeroMemory(buff, 128);
        timeout = FALSE;
    }

    return 0;
}