#include <winsock2.h>

#ifdef _WIN32
    WORD wVersionRequested;
    WSADATA wsaData;
    int err;
    int connectCount = 0;
    struct sockaddr_in RecvIndexAddr;
    int nNetTimeout= 3000;

    wVersionRequested = MAKEWORD(2,2);

    err = WSAStartup( wVersionRequested, &wsaData );
    if ( err != 0 ) {
        /* Tell the user that we couldn‘t find a usable */
        /* WinSock DLL.                                  */
        return FALSE;
    }

    /* Confirm that the WinSock DLL supports 2.0.*/
    /* Note that if the DLL supports versions greater    */
    /* than 2.0 in addition to 2.0, it will still return */
    /* 2.0 in wVersion since that is the version we      */

    /* requested.                                        */

    if ( LOBYTE( wsaData.wVersion ) != 2 ||
         HIBYTE( wsaData.wVersion ) != 2 ) {
        /* Tell the user that we couldn‘t find a usable */
        /* WinSock DLL.                                  */
        WSACleanup();
        return FALSE;
    }
#endif


CmakeLists.txt  添加 link_libraries(-lws2_32)

更改为win下跨平台的程序