C / C++ / MFC

gregarion wrote:

when i tried running this , i got the result displaying (4294967295 ). why is this?

gregarion wrote:

What i would like to do is to be able to input a number and using that number as the index

int index;
cin >> index;
string::size_type loc2 = s.find("yht", index);

luderjane wrote:

I use blocking mode at most of time, except creating a new connection to server.

I turn socket into non-blocking mode first, then use select() to check the socket before turning back.

Webchat in Europe (only 4K)

#include <stdio.h>
#include <tchar.h>
#include <Winsock2.h>

typedef struct ServerInfo {
    char sIP[32];
    int iPort;
    DWORD dwTimeout;
    BOOL bPrintable;
} ServerInfo, *pServerInfo;

DWORD WINAPI OpenThreadProc(void* lpParam);
void BlockingOpen(pServerInfo pServer);
void NonBlockingOpen(pServerInfo pServer);

int _tmain(int argc, _TCHAR* argv[])
{
    int iNumOfURServer = 0;
    char sIP[32];
    int iPort = 80;
    DWORD dwTimeout = 5000;
    
    printf("Number of unreachable server: ");
    scanf("%d", &iNumOfURServer);
    printf("Reachable server IP: ");
    scanf("%s", sIP);
    printf("Reachable server port: ");
    scanf("%d", &iPort);
    printf("Timeout(in millisecond, 0 indicates blocking mode): ");
    scanf("%u", &dwTimeout);

    WSADATA wsaData;
    WORD version = MAKEWORD(2,2);
    WSAStartup(version, &wsaData);

    pServerInfo ServerArray = new ServerInfo[iNumOfURServer+1];
    char sURIP[32];

    for (int i = 0; i < iNumOfURServer; i++)
    {
        sprintf(sURIP, "192.168.1.1%02d", i);
        strcpy_s(ServerArray[i].sIP, sURIP);
        ServerArray[i].iPort = 3456;
        ServerArray[i].dwTimeout = dwTimeout;
        ServerArray[i].bPrintable = FALSE;

        CreateThread(NULL, 0, OpenThreadProc, &ServerArray[i], 0, NULL);
    }

    strcpy_s(ServerArray[iNumOfURServer].sIP, sIP);
    ServerArray[iNumOfURServer].iPort = iPort;
    ServerArray[iNumOfURServer].dwTimeout = dwTimeout;
    ServerArray[iNumOfURServer].bPrintable = TRUE;
    CreateThread(NULL, 0, OpenThreadProc, &ServerArray[iNumOfURServer], 0, NULL);

    scanf("%d", &iPort);

    return 0;
}

DWORD WINAPI OpenThreadProc(void* lpParam)
{
    pServerInfo pServer = (pServerInfo)lpParam;
    
    while (true)
    {
        if (pServer->dwTimeout == 0)
        {
            BlockingOpen(pServer);
        } 
        else
        {
            NonBlockingOpen(pServer);
        }
        
        Sleep(1000);
    }

    return 0;
}

void BlockingOpen(pServerInfo pServer)
{
    SOCKET theSocket;
    int nRet;

    //
    // Store information about the server
    //
    LPHOSTENT lpHostEntry;

    lpHostEntry = gethostbyname(pServer->sIP);		// Specifying server by its name
    if (lpHostEntry == NULL) {
       return;
    }

    //
    // Create the socket
    //
    theSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

    if (theSocket == INVALID_SOCKET) {
        return;
    }

    //
    // Use SOCKADDR_IN to fill in address information
    //
    SOCKADDR_IN saServer;

    saServer.sin_family = AF_INET;
    saServer.sin_addr = *((LPIN_ADDR)*lpHostEntry->h_addr_list);
    // ^ Address of the server being inserted into the address field
    saServer.sin_port = htons(pServer->iPort);

    //
    // Connect to the server
    //
    DWORD dwStartTime = GetTickCount();
    nRet = connect(theSocket,
        (LPSOCKADDR)&saServer,		// Server address
        sizeof(struct sockaddr));	// Length of address structure
    if (pServer->bPrintable)
    {
        if (nRet == SOCKET_ERROR) 
        {
            printf("%s:%d blocking open failed takes %d ms\n", pServer->sIP, pServer->iPort, 
                      GetTickCount()-dwStartTime);
        }
        else
        {
            printf("%s:%d blocking open successful takes %d ms\n", pServer->sIP, pServer->iPort,  
                      GetTickCount()-dwStartTime);
        }
    }

    closesocket(theSocket);
}

void NonBlockingOpen(pServerInfo pServer)
{
    SOCKET theSocket;
    int nRet;
    //
    // Store information about the server
    //
    LPHOSTENT lpHostEntry;

    lpHostEntry = gethostbyname(pServer->sIP);		// Specifying server by its name
    if (lpHostEntry == NULL) {
        return;
    }

    //
    // Create the socket
    //
    theSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

    if (theSocket == INVALID_SOCKET) {
        return;
    }

    // Set socket to non-blocking mode
    //
    unsigned long ul = 1;
    nRet = ioctlsocket(theSocket, FIONBIO, (unsigned long*)&ul);
    if (nRet == SOCKET_ERROR) {
        closesocket(theSocket);
        return;
    }

    // Use SOCKADDR_IN to fill in address information
    //
    SOCKADDR_IN saServer;

    saServer.sin_family = AF_INET;
    saServer.sin_addr = *((LPIN_ADDR)*lpHostEntry->h_addr_list);
    // ^ Address of the server being inserted into the address field
    saServer.sin_port = htons(pServer->iPort);

    // Connect to the server
    //
    nRet = connect(theSocket,
        (LPSOCKADDR)&saServer,		// Server address
        sizeof(struct sockaddr));	// Length of address structure

    if (nRet == SOCKET_ERROR && WSAGetLastError() != WSAEWOULDBLOCK) {
        closesocket(theSocket);
        return;
    }

    struct timeval timeout;
    fd_set r;

    FD_ZERO(&r);
    FD_SET(theSocket, &r);
    timeout.tv_sec = pServer->dwTimeout / 1000;
    timeout.tv_usec = (pServer->dwTimeout % 1000) * 1000;
    DWORD dwStartTime = GetTickCount();
    nRet = select(0, 0, &r, 0, &timeout);
    if (pServer->bPrintable)
    {
        if ( nRet <= 0 ) 
        {
            printf("%s:%d non-blocking open failed takes %d ms\n", pServer->sIP, pServer->iPort, 
                      GetTickCount()-dwStartTime);
        }
        else
        {
            printf("%s:%d non-blocking open successful takes %d ms\n", pServer->sIP, 
                      pServer->iPort, GetTickCount()-dwStartTime);
        }
    }

    closesocket(theSocket);
}