跨平台socket 简单实现

header

void socket_init();
void socket_term();
int socket_create_acceptor( u_short port, bool reuse = false );
int socket_create_connector();
int socket_connect( int s, const char* address, u_short port );
int socket_accept( int s );
int socket_send( int s, const char* msg, int length );
void socket_close( int s );
bool socket_disconnected( int s );
int socket_setsockopt( int s, int opt );
int socket_getsockopt( int s, int opt, int& optval );

cpp

    void socket_init()
    { 
#ifdef _MSC_VER
        WORD version = MAKEWORD( 2, 2 );
        WSADATA data;
        WSAStartup( version, &data );
#else
        struct sigaction sa;
        sa.sa_handler = SIG_IGN;
        sigemptyset( &sa.sa_mask );
        sa.sa_flags = 0;
        sigaction( SIGPIPE, &sa, 0 );
#endif

    }

    void socket_term()
    {

#ifdef _MSC_VER
        WSACleanup();
#endif
    }

    int socket_create_acceptor(u_short port, bool reuse)
    {

        int socket = (int)(::socket( PF_INET, SOCK_STREAM, 0 ));
        if ( socket < 0 ) return -1;

        sockaddr_in address;
        socklen_t socklen;

        address.sin_family = PF_INET;
        address.sin_port = htons( port );
        address.sin_addr.s_addr = INADDR_ANY;
        socklen = sizeof( address );
        if( reuse )
            socket_setsockopt( socket, SO_REUSEADDR );

        int result = bind( socket, reinterpret_cast < sockaddr* > ( &address ),
            socklen );
        if ( result < 0 ) return -1;
        result = listen( socket, SOMAXCONN );
        if ( result < 0 ) return -1;
        return socket;

    }

    int socket_create_connector()
    {
        return (int)(::socket( PF_INET, SOCK_STREAM, IPPROTO_TCP ));
    }

    int socket_connect( int socket, const char* address, u_short port )
    {

        const char* hostname = socket_hostname( address );
        if( hostname == 0 ) return -1;

        sockaddr_in addr;
        addr.sin_family = PF_INET;
        addr.sin_port = htons( port );
        addr.sin_addr.s_addr = inet_addr( hostname );

        int result = connect( socket, reinterpret_cast < sockaddr* > ( &addr ),
            sizeof( addr ) );

        return result;

    }

    int socket_accept( int s )
    {

        if ( !socket_isValid( s ) ) return -1;
        return (int)(accept( s, 0, 0 ));

    }

    int socket_send( int s, const char* msg, int length )
    {
        return send( s, msg, length, 0 );
    }

    void socket_close( int s )
    {

        shutdown( s, 2 );
#ifdef _MSC_VER
        closesocket( s );
#else
        close( s );
#endif

    }

    bool socket_disconnected( int s )
    {

        char byte;
        return ::recv (s, &byte, sizeof (byte), MSG_PEEK) <= 0;

    }

    int socket_setsockopt( int s, int opt )
    {

        int level = SOL_SOCKET;
        if( opt == TCP_NODELAY )
            level = IPPROTO_TCP;

#ifdef _MSC_VER
        BOOL optval = TRUE;
        return ::setsockopt( s, level, opt,
            ( char* ) & optval, sizeof( optval ) );
#else
        int optval = 1;
        return ::setsockopt( s, level, opt,
            &optval, sizeof( optval ) );
#endif
    }

    int socket_getsockopt( int s, int opt, int& optval )
    {

        int level = SOL_SOCKET;
        if( opt == TCP_NODELAY )
            level = IPPROTO_TCP;

#ifdef _MSC_VER
        int length;
#else
        socklen_t length;
#endif

        return ::getsockopt( s, level, opt, 
            ( char* ) & optval, & length );

    }

服务器端 跨平台select 使用, 例子中支持最多5个连接（客户端简单一些）

 

    int socket_num;
    int conns = 0;
    char buf[512];
    int new_fd;
    fd_set fdsr;
    unsigned int fd_A[5];
    memset(fd_A, 0, sizeof(fd_A));

    socket_init();

    socket_num = socket_create_acceptor(14001);

    while(!shutdown){
        FD_ZERO( &fdsr );
        FD_SET((u_int)socket_num,&fdsr);

        for (int i = 0; i < 5; i++)
        {
            if (fd_A[i] != 0)
                FD_SET(fd_A[i], &fdsr);
        }

        int result = select( FD_SETSIZE, &fdsr, 0, 0, 0);

        if ( result < 0 )
            break;
        else if (result == 0)
            continue;

        // check every fd in the set
        for (int i = 0; i < conns; i++)
        {
            if (FD_ISSET(fd_A[i], &fdsr))
            {
                int ret = recv(fd_A[i], buf, sizeof(buf), 0);
                if (ret <= 0)
                {
                    socket_close(fd_A[i]);
                    FD_CLR(fd_A[i], &fdsr);
                    fd_A[i] = 0;
                }
                else
                {
                    //handle message
                }
            }
        }
        if (FD_ISSET(socket_num, &fdsr))
        {
            //handle new connection
            new_fd = socket_accept(socket_num);
            if (new_fd <= 0)
                continue;
            if (conns < 5)
                fd_A[conns++] = new_fd;
            else
                socket_close(new_fd);
        }

    }
    for (int i = 0; i < 5; i++)
    {
        if (fd_A[i] != 0)
            socket_close(fd_A[i]);
    }
    socket_term();