c - 如何查看定时任务是否在后台运行？

Question

下面的代码用于通过 udp 层的套接字从主机接收数据。我的项目中支持一些 API，我创建了一个计时器任务，用于每 2 毫秒、10 毫秒等调用一次任务。

我正在使用远程 C/C++ 应用程序在 Eclipse IDE 中的嵌入式 PC 目标上调试此程序。我在 CreateSocket 函数中调用 maketimer (alarm)。但是如何查看定时任务在后台每隔2ms、10ms、100ms调用函数TASK1、TASK2、TASK3呢？

#include "MAIN.h"

#define BILLION  1000000L

timer_t firstTimerID, secondTimerID, thirdTimerID;
double Task2ms_Raster, Task10ms_Raster, Task100ms_Raster ;

int connectedSocket, acceptSocket;
struct sockaddr_in addr;
struct sockaddr client, dest;
char buf[128];
long rc, sentbytes;
int port = 18017;


void TASK1(Task2ms_Raster)
{

    struct timespec start, stop;
    uint32 StartTime, StopTime;

    if( (StartTime = clock_gettime( CLOCK_REALTIME, &start)) == -1 ) 
    {
        perror("clock gettime");

    }

    // return EXIT_SUCCESS;

    /* Trigger DAQ for the 2ms XCP raster. */
    if( XCPEVENT_DAQ_OVERLOAD & Xcp_DoDaqForEvent_2msRstr( ))
    {
        ++numDaqOverload2ms;
    }

    /* Update those variables which are modified every 2ms. */
    counter32 += slope32;

    /* Trigger STIM for the 2ms XCP raster. */
    if( enableBypass2ms )
    {
        if( XCPEVENT_MISSING_DTO & Xcp_DoStimForEvent_2msRstr( ) )
        {
            ++numMissingDto2ms;
        }
    }
    if( (StopTime = clock_gettime( CLOCK_REALTIME, &stop)) == -1 ) 
    {
        perror( "clock gettime" );
    }

    duration2ms = ( stop.tv_sec - start.tv_sec )
        + (double)( stop.tv_nsec - start.tv_nsec )
        / (double)BILLION;
    printf( "time difference is= %ld\n", duration2ms );
}

void TASK2(Task10ms_Raster)
{
    struct timespec start, stop;

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

    /* Trigger DAQ for the 10ms XCP raster. */
    if( XCPEVENT_DAQ_OVERLOAD & Xcp_DoDaqForEvent_10msRstr( ))
    {
        ++numDaqOverload10ms;
    }

    /* Update those variables which are modified every 10ms. */
    counter16 += slope16;

    /* Trigger STIM for the 10ms XCP raster. */
    if( enableBypass10ms )
    {
        if( XCPEVENT_MISSING_DTO & Xcp_DoStimForEvent_10msRstr( ) )
        {
            ++numMissingDto10ms;
        }
    }

    if( clock_gettime( CLOCK_REALTIME, &stop) == -1 ) 
    {
        perror( "clock gettime" );
    }
    XCP_FN_TYPE Xcp_CmdProcessor ( );

    duration10ms = ( stop.tv_sec - start.tv_sec )
        + (double)( stop.tv_nsec - start.tv_nsec )
        / (double)BILLION;
    printf( "time difference is= %ld\n", duration10ms );
}


void TASK3(Task100ms_Raster)
{
    struct timespec start, stop;

    if( clock_gettime( CLOCK_REALTIME, &start) == -1 ) 
    {
        perror( "clock gettime" );

    }

    /* Trigger DAQ for the 100ms XCP raster. */
    if( XCPEVENT_DAQ_OVERLOAD & Xcp_DoDaqForEvent_100msRstr( ))
    {
        ++numDaqOverload100ms;
    }

    /* Update those variables which are modified every 100ms. */
    counter8 += slope8;


    /* Trigger STIM for the 100ms XCP raster. */
    if( enableBypass100ms )
    {
        if( XCPEVENT_MISSING_DTO & Xcp_DoStimForEvent_100msRstr( ) )
        {
            ++numMissingDto100ms;
        }
    }

    if((clock_gettime( CLOCK_REALTIME, &stop)) == -1 ) 
    {
        perror( "clock gettime" );
    }

    duration100ms = ( stop.tv_sec - start.tv_sec )
        + (double)( stop.tv_nsec - start.tv_nsec )
        / (double)BILLION;
    printf( "time difference is= %ld\n", duration100ms );
}

static void timerHandler( int sig, siginfo_t *si, void *uc )
{
    timer_t *tidp;

    tidp = si->si_value.sival_ptr;

    if ( *tidp == firstTimerID )

        TASK1(Task2ms_Raster);
    else if ( *tidp == secondTimerID )
        TASK2(Task10ms_Raster);
    else if ( *tidp == thirdTimerID )
        TASK3(Task100ms_Raster);
}

static int makeTimer( char *name, timer_t *timerID, int expireMS, int intervalMS )
{
    struct sigevent         te;
    struct itimerspec       its;
    struct sigaction        sa;
    int                     sigNo = SIGRTMIN;

    /* Set up signal handler. */
    sa.sa_flags = SA_SIGINFO;
    sa.sa_sigaction = timerHandler;
    sigemptyset(&sa.sa_mask);
    if (sigaction(sigNo, &sa, NULL) == -1)
    {
        perror("sigaction");
    }

    /* Set and enable alarm */
    te.sigev_notify = SIGEV_SIGNAL;
    te.sigev_signo = sigNo;
    te.sigev_value.sival_ptr = timerID;
    timer_create(CLOCK_REALTIME, &te, timerID);

    its.it_interval.tv_sec = 0;
    its.it_interval.tv_nsec = intervalMS * 1000000;
    its.it_value.tv_sec = 0;
    its.it_value.tv_nsec = expireMS * 1000000;
    timer_settime(*timerID, 0, &its, NULL);

    return 1;
}

int CreateSocket()
{
    if(rc!=0)
    {
        printf("socket failure code: %ld\n",rc);

        return 1;
    }

    else

    {
        printf("socket started!\n");
    }

    // 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));

    if(rc== -1)
    {

        printf("Failure: listen, failure code:\n");

        return 1;
    }
    else
    {
        printf("Socket an port %d \n",port);
    }


    while(rc!=-1)
    {
        rc= recvfrom(acceptSocket,buf,128,0,(struct sockaddr*)&client, sizeof(client));
        if(rc==0)
        {
            printf("Server has no connection..\n");
            break;
        }
        if(rc==-1)
        {
            printf("failure: recv, failure code\n");
            break;
        }
        XcpIp_RxCallback( (uint16) rc, (uint8*) buf, (uint16) port );

        makeTimer("First Timer", &firstTimerID, 2, 2);   //2ms
        makeTimer("Second Timer", &secondTimerID, 10, 10);    //10ms
        makeTimer("Third Timer", &thirdTimerID, 100, 100);  //100ms

        //    buf[rc]='\0';
        //    printf("Client sendet: %s\n",buf);
        //    sprintf(buf2,"Du mich auch %s",buf);
        //    rc=sendto(connectedSocket,buf2,strlen(buf2),0);
    }

    close(acceptSocket);

    return 0;
}

int main()
{
    Xcp_Initialize();
    CreateSocket();
    return 0;
}

void XcpApp_IpTransmit( uint16 XcpPort,  Xcp_StatePtr8 pBytes, uint16 numBytes )
{
    if ((long)XcpPort==port)
    {
        sentbytes = sendto(acceptSocket,(char*)pBytes,(long)numBytes,0, (struct sockaddr*) &dest, sizeof(dest));
    }
    XcpIp_TxCallback(port,(uint16)sentbytes);
}

Answer 1

阅读time(7)和 signal(7) .

顺便说一句，您的 BILLION 是错误的。你可能应该有

#define BILLION 1.0e9

^{(因为您仅在浮点表达式中使用它)}

您可以拥有三个线程(读取 pthreads tutorial )，一个用于 TASK1，一个用于 TASK2，一个用于 TASK3(可能使用 clock_nanosleep(2) ...)。或者(最好)你可以有一个 event loop (围绕例如 poll(2) 或 ppoll(2) 多路复用调用....)，也许还使用 timerfd_create(2)获取计时器事件，并管理套接字。参见 this example of poll-based event loop .您应该调整它以也使用通过 timerfd_create 获得的文件描述符。您还可以使用一些事件循环库，如 libevent或 libev

请注意，2 毫秒是一个非常小的延迟。 (您希望它有多可靠？)

阅读Advanced Linux Programming