c - 多线程程序中不接收UDP并输出数据

Question

uint64_t GetTimeStamp()
{
    struct timespec start;

    if ((clock_gettime( CLOCK_MONOTONIC, &start)) == -1)
    {
        perror("clock gettime\n");
    }

    return(start.tv_sec + start.tv_nsec * 1e-9);                // seconds
}

const struct sigevent *intHandler(void *arg, int id)
{
    start_clock = ClockCycles();
    // printf("start clock: %lld\n", start_clock);

    return(&event);
}

void *ConfigureISR()
{
    // Get IO privilege
    ThreadCtl( _NTO_TCTL_IO, 0 );
    // Setup COID and event
    SIGEV_INTR_INIT( &event);

    interruptID = InterruptAttach(intrNum, intHandler, NULL, 0, 0);
    if (interruptID == -1)
    {
        fprintf(stderr, "can't attach to IRQ %d\n", intrNum );
        perror(NULL);
        exit(EXIT_FAILURE);
    }

    while (loop)
    {
        InterruptWait(0, NULL);
        end_clock = ClockCycles();
        InterruptLatency = (uint32) ((end_clock - start_clock) * 1000000 / (SYSPAGE_ENTRY(qtime)->cycles_per_sec));
        printf("Current Interrupt Latency microseconds: %ld\n", InterruptLatency);
        InterruptUnmask(intrNum, interruptID);
        measurements[17] = InterruptLatency;
    }
    return(EXIT_SUCCESS);
}

int CreateSocket()
{
    // pthread_attr_t attr;
    // Socket creation for UDP

    acceptSocket = socket(AF_INET, SOCK_DGRAM, 0);

    if (acceptSocket == -1)
    {
        printf("Failure: socket creation is failed, failure code\n");
        return 1;
    }
    else
    {
        printf("Socket started!\n");
    }

    memset(&addr, 0, sizeof(addr));

    addr.sin_family = AF_INET;
    addr.sin_port = htons(port);
    addr.sin_addr.s_addr = htonl(INADDR_ANY);

    rc = bind(acceptSocket, (struct sockaddr *)&addr, sizeof(addr));

    fcntl(acceptSocket, O_NONBLOCK);

    if (rc == -1)
    {
        printf("Oh dear, something went wrong with bind()! %s\n", strerror(errno));
        return -1;
    }
    else
    {
        printf("Socket an port %d \n", port);
    }
    return acceptSocket;
}

int main(int argc, char *argv[])
{
    pthread_t thread_id, thread_id1;

    Xcp_Initialize();

    pthread_create(&thread_id1, NULL, &ConfigureISR, NULL);

    if ((sock = CreateSocket()) < 0)
    {
        perror("Create_socket");
        exit(1);
    }

    if (pthread_create(&thread_id, NULL, &rastertask, NULL))
    {
        perror("pthread_create");
        exit(1);
    }

    do
    {
        socklen_t len;
        len = sizeof(client);
        printf("NEW DATA ARRIVED\n");
        // non blocking mode : MSG_DONTWAIT
        rc = recvfrom(sock, buf, 256, 0, (struct sockaddr *) &client, &len);
        Receive = GetTimeStamp();
        receiveTime = (uint32) (Receive / 1000000);
        printf("Receive time: %lu\n", receiveTime);
        //  printf("RECEIVE from Time in microseconds: %lu\n",  ReceiveTimestamp);
        // measurements[19] = ReceiveTimestamp;
        if (rc == 0)
        {
            printf("Server has no connection..\n");
            loop = 0;
            break;
        }
        if (rc == -1)
        {
            if (errno == SIGINT)
                continue;
            printf("Oh dear, something went wrong with read()! s\n", strerror(errno));
            loop = 0;
            break;
        }

        XcpIp_RxCallback( (uint16) rc, (uint8 *) buf, (uint16) port );
    } while (1);


    close(sock);

    return 0;
}

上面是服务器代码，通过ip地址和端口号接收数据。

稍后将数据发送回客户端。我正在接收数据，但在接收数据后，获取时间戳(您可以在上面的代码中看到:Send= GetTimeStamp())。

为什么不打印任何内容？我正在通过套接字接收数据，并且我给出了 printf("new data returned\n"); 然后它也没有打印。我也没有在那里收到任何时间!有人可以告诉我这可能是什么原因吗？

Answer 1

您的GetTimeStamp()函数返回一个uint64_t；返回语句是:

return (start.tv_sec + start.tv_nsec * 1e-9);

这会创建一个 double 值(1e-9 是一个 double 常量)，然后将其截断为整数，就像您已返回:

return (start.tv_sec);

请注意，这会为您提供以秒为单位的时间(自纪元 - 1970-01-01 00:00:00 +00:00 开始)。

也许你想要:

return (start.tv_sec * 1E9 + start.tv_nsec);

这为您提供了自纪元以来的纳秒总数。这可能与您遇到的其他问题无关，但无法发送合理的值意味着您将无法接收合理的值，因此您应该确定您期望从 GetTimeStamp() 获得什么值。例如:

    Receive = GetTimeStamp();
    receiveTime = (uint32) (Receive / 1000000);
    printf("Receive time: %lu\n", receiveTime);

这将打印一个值，例如 1400(因为当前时间戳约为 1400755363 = 2014-05-22 10:42:43)，因此该值除以 100 万就是 1400。