golang判断tcp是否断开的方法

struct TCP_KEEPALIVE { 

    unsigned long onoff; 

    unsigned long keepalivetime; 

    unsigned long keepaliveinterval; 

} ; 

#define SIO_KEEPALIVE_VALS _WSAIOW(IOC_VENDOR,4) 

/* KeepAlive实现 */ 

void set_keepalive (SOCKET s) 

{ 

    BOOL bKeepAlive = TRUE; 

    int nRet = ::setsockopt(s, SOL_SOCKET, SO_KEEPALIVE, (char*)&bKeepAlive, sizeof(bKeepAlive)); 

    if (nRet == SOCKET_ERROR) 

    { 

        return ; 

    } 

    /* 输入参数 */ 

    struct TCP_KEEPALIVE inKeepAlive = {0};  

    unsigned long ulInLen = sizeof(struct TCP_KEEPALIVE); 

    /* 输出参数 */ 

    struct TCP_KEEPALIVE outKeepAlive = {0};  

    unsigned long ulOutLen = sizeof(struct TCP_KEEPALIVE); 

    unsigned long ulBytesReturn = 0; 

    int ret = 0; 

    /* 设置keepalive 为5秒，并且发送次数为3次 */ 

    inKeepAlive.onoff             = 1; 

    /* 2次keepalive探测间隔时间 */ 

    inKeepAlive.keepaliveinterval = 5000;  

    /* 开始首次keepalive探测前的tcp空闲时间 */ 

    inKeepAlive.keepalivetime     = 5000;  

    ret = WSAIoctl((unsigned int)s, 

            SIO_KEEPALIVE_VALS, 

            (LPVOID)&inKeepAlive,  

            ulInLen, 

            (LPVOID)&outKeepAlive,  

            ulOutLen, 

            &ulBytesReturn,  

            NULL,  

            NULL); 

    if (ret == SOCKET_ERROR) 

    { 

        printf ("error: %d\n", WSAGetLastError()); 

    } 

}