#define million 1000000L timer_t firstTimerID, secondTimerID, thirdTimerID; double Task2ms_Raster, Task10ms_Raster, Task100ms_Raster; struct sockaddr_in addr, client; int acceptSocket; char buf[256]; long rc, sentbytes; int port = 18033; void TASK1(Task2ms_Raster) { struct timespec start, stop; uint32 startTime, stopTime; if( (startTime = clock_gettime( CLOCK_REALTIME, &start)) == -1 ) { perror("clock gettime"); } startTime =start.tv_sec + 0.0000001 * start.tv_nsec; // printf("start time is %lf", StartTime); // 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" ); } stopTime = stop.tv_sec + 0.0000001 * stop.tv_nsec; //printf("stop time is %ld", stopTime); duration2ms = (uint32)(stopTime- startTime); // printf( "time difference is= %ld\n", duration2ms ); } void TASK3(Task100ms_Raster) { struct timespec start, stop; uint32 startTime, stopTime; if( (startTime = clock_gettime( CLOCK_REALTIME, &start)) == -1 ) { perror("clock gettime"); } startTime =start.tv_sec + 0.0000001 * start.tv_nsec; // printf("start time is %lf", startTime); /* 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((stopTime = clock_gettime( CLOCK_REALTIME, &stop)) == -1 ) { perror( "clock gettime" ); } stopTime = stop.tv_sec + 0.0000001 * stop.tv_nsec; // printf("stop time is %lf", stopTime); Xcp_CmdProcessor(); duration100ms = ( stop.tv_sec - start.tv_sec ) + (double)( stop.tv_nsec - start.tv_nsec ) / (double)million; // printf( "time difference is= %ld\n", duration100ms ); } /*The handler checks that the value stored in sival_ptr matches a given timerID variable. The sival_ptr is the same as the one we set in makeTimer(), though here it lives in a different structure. Obviously, it got copied from there to here on the way to this signal handler. The point is that the timerID is what is used to determine which timer just went off and determine what to do next */ 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); } /* The function takes a pointer to a timer_t variable that will be filled with the timer ID created by timer_create(). This pointer is also saved in the sival_ptr variable right before calling timer_create(). In this function notice that we always use the SIGRTMIN signal, so expiration of any timer causes this signal to be raised. The signal handler I've written for that signal is timerHandler. */ 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() { socklen_t len = sizeof(client); // 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); } if(acceptSocket == -1) { printf("Fehler: accept, fehler code:\n"); return 1; } else { while(rc!=-1) { rc=recvfrom(acceptSocket,buf, 256, 0, (struct sockaddr*) &client, &len); if(rc==0) { printf("Server has no connection..\n"); break; } if(rc==-1) { printf("something went wrong with data %s", strerror(errno)); break; } XcpIp_RxCallback( (uint16) rc, (uint8*) buf, (uint16) port ); // create a timer makeTimer("First Timer", &firstTimerID, 2, 2); //2ms makeTimer("Second Timer", &secondTimerID, 10, 10); //10ms makeTimer("Third Timer", &thirdTimerID, 100, 100); //100ms } } 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*)&client, sizeof(client)); } XcpIp_TxCallback(port,(uint16)sentbytes); } 我正在研究客户端和服务器体系结构。 服务器代码如上所示，我创build了一个套接字，通过IP地址和端口号从客户端接收请求。 服务器正在等待来自客户端的请求，并将响应发送回客户端。 我还创build了定时器，每2ms，10ms和100ms调用te任务。 我还没有创build一个计时器任务分离的线程。 刚创build一个处理程序来处理（信号处理程序）。 当客户端向服务器发送请求时，我接收到recvfrom api中的数据，然后调用maketimer（2ms），之后它不是从2ms任务中提取出来的。
客户端是一种用于将数据发送到服务器的工具（INCA）。 我正在linux操作系统上工作。
有人能告诉我上面的程序有什么错？
您需要为while（rc！= – 1）循环创建单独的线程，因为recvfrom（）是一个阻塞函数。 它将您的线程置于非活动状态，直到新数据到来。