C Language Socket multithreaded programming limit client connections

       This article mainly introduces C language socket multithreaded programming, you can limit the number of client connections, we refer to the use of the bar

      First, some of the function definitions to use for Multithreading:     Code as follows: DWORD WINAPI Processclientrequests (LPVOID lpparam)  //new Thread The function definition that will be executed {      return 0;}   HANDLE Handler=createthread (NULL, 0, processclientrequests, &clien Tsocket, 0, NULL);  //Here is simpler, &clientsocket is a pointer to the parameters of the new thread passed from the main thread     waitformultipleobjects (maxclients, threads, TRUE, INFINITE);  //is used to block the main thread until all created child threads complete the task before continuing with the following code   for (int i=0;i<maxclients; i++) {    CloseHandle ( Threads[i]);      //created handle of each child thread will be saved in the handle array, this function is used to close the handle corresponding to the thread space}       server-side program   The main thread code is as follows:   code as follows: #define MAXCLIENTS 3          //macro definition, up to 3 client connections   int main () {  & nbsp Wsadata Wsadata;     WSAStartup (Makeword (2, 2), &wsadata);     HANDLE threads[maxclients];       SOCKET s=socket (pf_inet, Sock_stream, ipproto_tcp);       sockaddr_in sockaddr;   &NBsp Sockaddr.sin_family=pf_inet;     SOCKADDR.SIN_ADDR. S_un. S_ADDR=INET_ADDR ("127.0.0.1");     Sockaddr.sin_port=htons (9000);     Bind (s, (sockaddr*) &sockaddr, sizeof (SOCKADDR));       Listen (s, 1);       printf ("listening on port [%D].N", 9000);       int existingclientcount=0;     while (TRUE)     {        SOCKADDR clientaddr         INT Size=sizeof (SOCKADDR);           SOCKET Clientsocket;         clientsocket=accept (S, &clientaddr, &size);         printf ("***sys***    new client TOUCHED.N");           if (existingclientcount<maxclients)      //Determine if the maximum number of connections has been exceeded   &NB Sp     {          Threads[existingclientcount++]=createthread (NULL, 0, PROCESSCLI Entrequests, &clientsockeT, 0, NULL);  //start new thread, and socket incoming        }         else         {&NB Sp           char* msg= "exceeded Max incoming requests, would refused this connect!rn";             Send (Clientsocket, MSG, strlen (msg) +sizeof (char), NULL);      //Send reject connection message to client             printf ("***sys***    REFUSED.N");             closesocket (clientsocket);                                   &NB Sp Release resources             break;        }     {      printf ("Maximize clients occurred for D%.rn", maxclient S);       WaitForMultipleObjects (maxclients, threads, TRUE, INFINITE);          //Waiting for all child threads until the end of       Closesocket (s);     for (int i=0;i<maxclients; i++)     {        CloseHandle (threads[i)) &nbsp ;                                   &NB Sp    //cleanup thread resources    }       WSACleanup ();       printf ("Cleared All.rn");       GetChar ();       exit (0); }       sub-threading function definition     code is as follows: DWORD WINAPI Processclientrequests (lpvoid lpparam) {    sock et* clientsocket= (socket*) Lpparam;  //here needs to be cast, note: pointer type       char* msg= "Hello, my Client.rn";     Send (*clientsocket, MSG, strlen (msg) +sizeof (char), NULL);     printf ("***sys***    HELLO.N");       while (TRUE)     {        Char buffer[maxbyte]={0};     &NBSP ;   recv (*clientsocket, buffer, maxbyte, NULL);   &NBSp     if (strcmp (buffer, "exit") ==0         {            char* Msg_bye= "Bye.rn";             Send (*clientsocket, Msg_bye, strlen (Msg_bye) +sizeof (char), NULL);             break;        }         printf ("***client***    %SN", buffer);    }       closesocket (*clientsocket);       return 0; }