У моей игры с сокетами есть проблемы, и я не могу понять, почему

Question

Код теперь работает нормально, но я хочу задать вам несколько вопросов. Первый: почему сообщения принимаются медленно (около 1 секунды)? (не локально) Второй вопрос: зачем мне функция сна в строке 213? Третий вопрос: почему мне нужно подтверждение от recv в receiveMessage void, чтобы получать все сообщения?

На linux сокете все в порядке.

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <WS2tcpip.h>

#pragma comment (lib, "ws2_32.lib")

#define MAXSIZE 1024
#define PORT 13333

#define FINISH_GAME "cmdfinishgame"
#define RESET_GAME "cmdresetgame"
#define CLOSE_SOCKET "cmdclosesocket"
#define CLEAR_CONSOLE "cmdclearconsole"

const char trustedLetters[27] = "abcdefghijklmnopqrstuvwxyz";

SOCKET serverSocket;
SOCKET clientSocket;

char buffer[MAXSIZE];

char usedLetters[27] = "";

int choose;

void setupServer();
void setupClient();

void sendMessage(char * message);
void receiveMessage(char * message);

int setupGameForServer();
int setupGameForClient();

void startGame();
void spectGame();

void getAUXofStr(char * _Src, char * _Dest);
void spaceString(char * _Src, char * _Dest);
void getChar(char *c);
void waitForUserInput();
void replace(char * _Str, char _Which, char _With);

main. c:

#include "main.h"

int main()
{
    while (1)
    {

        system("cls");

        printf("----------------------- \n");
        printf("[1] Crea una stanza     \n");
        printf("[2] Entra in una stanza \n");
        printf("----------------------- \n\n");

        printf("Scelta: ");
        scanf("%s", buffer);
        printf("\n");

        choose = atoi(buffer);
        if (choose == 1)
        {
            //Inizializzo lato server
            setupServer();

            //Aspetto che qualcuno si connetta
            SOCKADDR_IN clientInfo;
            int clientSize = sizeof(clientInfo);

            clientSocket = accept(serverSocket, (LPSOCKADDR)&clientInfo, &clientSize);
            if (clientSocket == INVALID_SOCKET)
            {
                exit(1);
            }

            closesocket(serverSocket);

            //in
            while (setupGameForServer() == 0);

            break;
        }
        else if (choose == 2)
        {
            //Inizializzo lato client
            setupClient();

            while (setupGameForClient() == 0);

            break;
        }
        else if (choose == 99)
        {
            break;
        }
    }

    closesocket(clientSocket);

    WSACleanup();

    return 0;
}

int setupGameForServer()
{
    memset(usedLetters, 0, sizeof(usedLetters));
    memset(buffer, 0, sizeof(buffer));



    //Inizia nuova partita
    while (1)
    {
        system("cls");

        printf("---------------------------- \n");
        printf("[1] Inizia nuova partita     \n");
        printf("[2] Chiudi                   \n");
        printf("---------------------------- \n\n");

        printf("Scelta: ");
        scanf("%s", buffer);
        printf("\n");

        choose = atoi(buffer);
        if (choose == 1)
        {
            sendMessage(RESET_GAME);
            break;
        }
        else if (choose == 2)
        {
            sendMessage(CLOSE_SOCKET);
            return 1;
        }
        else
        {
            printf("Errore! Inserire un opzione valida! \n\n\n");
            waitForUserInput();
        }
    }
    //-------------

    //Chi indovina?
    while (1)
    {
        system("cls");

        printf("---------------------- \n");
        printf("[1] Indovina il server \n");
        printf("[2] Indovina il client \n");
        printf("---------------------- \n\n");

        printf("Scelta: ");
        scanf("%s", buffer);
        printf("\n");

        choose = atoi(buffer);
        if (choose == 1)
        {
            sendMessage("1");

            startGame();
        }
        else if (choose == 2)
        {
            sendMessage("2");

            printf("Inserisci la frase: ");
            scanf(" %[^\n]", buffer);
            printf("\n");

            sendMessage(buffer);

            spectGame();
        }
        else
        {
            printf("Errore! Inserire un opzione valida! \n\n\n");
            waitForUserInput();
            continue;
        }

        break;
    }
    //-------------

    return 0;
}

int setupGameForClient()
{

    //
    receiveMessage(buffer);
    if (strcmp(buffer, RESET_GAME) == 0)
    {
        memset(usedLetters, 0, sizeof(usedLetters));
        memset(buffer, 0, sizeof(buffer));
    }
    else if (strcmp(buffer, CLOSE_SOCKET) == 0)
    {
        return 1;
    }


    Sleep(10);
    //printf("OK!"); //wtf?

    //
    receiveMessage(buffer);

    int i = atoi(buffer);
    if (i == 1)
    {

        printf("Inserisci la frase: ");
        scanf(" %[^\n]", buffer);
        printf("\n");

        sendMessage(buffer);

        spectGame();
    }
    else if (i == 2)
    {
        startGame();
    }

    return 0;
}

void setupServer()
{
    //Inizializzazione winsock
    WSADATA wsaData;
    WORD version = MAKEWORD(2, 2);

    if (WSAStartup(version, &wsaData))
    {
        exit(1);
    }

    //Creazione socket
    serverSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (serverSocket == INVALID_SOCKET)
    {
        exit(1);
    }

    //Bind dell'ip e della porta
    SOCKADDR_IN serverInfo;
    serverInfo.sin_family = AF_INET;
    serverInfo.sin_addr.s_addr = ADDR_ANY;
    serverInfo.sin_port = htons(PORT);

    bind(serverSocket, (LPSOCKADDR)&serverInfo, sizeof(serverInfo));

    //Messa del socket in ascolto
    listen(serverSocket, 1);
}

void setupClient()
{
    //Inizializzazione winsock
    WSADATA wsaData;
    WORD version = MAKEWORD(2, 2);

    if (WSAStartup(version, &wsaData))
    {
        exit(1);
    }

    //Creazione socket
    clientSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (clientSocket == INVALID_SOCKET)
    {
        exit(1);
    }

    //ip
    char ip[16];
    printf("Inserisci ip: ");
    scanf("%s", ip);
    printf("\n");

    //Mi connetto al server
    SOCKADDR_IN clientInfo;
    clientInfo.sin_family = AF_INET;
    clientInfo.sin_addr.s_addr = inet_addr(ip);
    clientInfo.sin_port = htons(PORT);

    connect(clientSocket, (LPSOCKADDR)&clientInfo, sizeof(clientInfo));
}

void startGame()
{
    receiveMessage(buffer);

    char *phrase;
    char *phraseAUX;

    phrase = (char *)malloc(strlen(buffer) * sizeof(char));
    phraseAUX = (char *)malloc(strlen(buffer) * sizeof(char));

    memcpy(phrase, buffer, strlen(buffer));

    phrase[strlen(buffer)] = '\0';
    phraseAUX[strlen(buffer)] = '\0';

    getAUXofStr(phrase, phraseAUX);

    system("cls");
    sendMessage(CLEAR_CONSOLE);

    char c;
    int flag = 0;
    int lives = 5;
    while (1)
    {

        //stampo lo status
        spaceString(phraseAUX, buffer);
        printf(buffer);
        printf("\n");
        sendMessage(buffer);
        sendMessage("\n");

        snprintf(buffer, 10, "%d", lives);
        printf("Vite rimaste: ");
        printf(buffer);
        printf("\n");
        sendMessage("Vite rimaste: ");
        sendMessage(buffer);
        sendMessage("\n");

        //Vedo se ho vinto
        if (strcmp(phrase, phraseAUX) == 0)
        {

            printf("Hai vinto! \n");
            sendMessage("Hai scelto una parola troppo easy colione! \n");

            break;
        }

        //Vedo se ho perso
        if (lives <= 0)
        {

            printf("Hai perso! La parola era: \"%s\"\n", phrase);
            sendMessage("Il tuo amico finocchio ha perso! GGEZ! \n");

            break;
        }

        //Inserimento carattere
        printf("Inserisci carattere: ");
        getChar(&c);
        printf("\n");

        system("cls");
        sendMessage(CLEAR_CONSOLE);

        //Vedo se la lettera è valida
        flag = 0;
        for (int i = 0; i < strlen(usedLetters); i++)
        {

            if (tolower(c) == usedLetters[i])
            {

                printf("Lettera già utilizzata! \n");

                sendMessage("Il tuo amico non capisce un cazzo, ha riinserito la stessa lettera! \n");

                flag = 1;

                break;
            }
        }

        if (flag)
            continue;
        else
            strncat(usedLetters, &c, 1);

        //Sostituisco la lettera nella stringa ausiliaria
        flag = 0;
        for (int i = 0; i < strlen(phrase); i++)
        {

            if (tolower(c) == tolower(phrase[i]))
            {

                phraseAUX[i] = phrase[i];
                flag = 1;
            }
        }

        if (!flag)
            lives -= 1;
    }

    waitForUserInput();

    sendMessage(FINISH_GAME);

    printf("\n\n");
}

void spectGame()
{

    while (1)
    {
        receiveMessage(buffer);

        if (strcmp(buffer, CLEAR_CONSOLE) == 0)
        {
            system("cls");
        }
        else if (strcmp(buffer, FINISH_GAME) == 0)
        {
            break;
        }
        else
        {
            printf("%s", buffer);
        }
    }
}

void receiveMessage(char *message)
{
    int result;

    memset(message, 0, sizeof(message));

    //u_long mode = 1;  // 1 to enable non-blocking socket
    //ioctlsocket(clientSocket, FIONREAD, &mode);

    result = recv(clientSocket, message, MAXSIZE, 0);
    if (result == 0)
    {
        exit(1);
    }

    send(clientSocket, "1", 2, 0);
}

void sendMessage(char *message)
{
    int result;
    char localBuffer[2];

    //u_long mode = 1;  // 1 to enable non-blocking socket
    //ioctlsocket(clientSocket, FIONBIO, &mode);

    result = send(clientSocket, message, (int)strlen(message) + 1, 0);
    if (result == 0)
    {
        exit(1);
    }

    recv(clientSocket, localBuffer, 2, 0);
    if (strcmp(localBuffer, "1") != 0) {
        waitForUserInput();
        exit(1);
    }

}

void getChar(char *c)
{
    char str[MAXSIZE];

    scanf("%s", str);

    *c = str[0];
}

void getAUXofStr(char *_Src, char *_Dest)
{
    char trustedLetters[] = "abcdefghijklmnopqrstuvwxyz";

    int flag = 0;
    for (int s1 = 0; s1 < strlen(_Src); s1 += 1)
    {
        flag = 0;

        for (int s2 = 0; s2 < strlen(trustedLetters); s2 += 1)
        {

            if (tolower(_Src[s1]) == trustedLetters[s2])
            {

                _Dest[s1] = '_';

                flag = 1;

                break;
            }
        }

        if (!flag)
            _Dest[s1] = _Src[s1];
    }
}

void spaceString(char *_Src, char *_Dest)
{
    char finalstr[MAXSIZE];
    char space = ' ';

    ZeroMemory(finalstr, sizeof(finalstr));

    for (int s1 = 0; s1 < strlen(_Src); s1 += 1)
    {

        strncat(finalstr, &_Src[s1], 1);
        strncat(finalstr, &space, 1);
    }

    strcpy(_Dest, finalstr);
}

void waitForUserInput()
{
    printf("Premere un tasto per continuare...\n");
    fflush(stdin);
    getchar();
}