#include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <signal.h> #include <string.h> #include <sys/types.h> #include <sys/wait.h> #define BUF_SIZE 26 int pipefd[2]; void sig_alrm(int signo){ char buf[BUF_SIZE]; int cnt = 0; printf("pid: %d, sig=%d ", getpid(), signo); for (char c = 'a'; c <= 'z'; c++) buf[cnt++] = c; write(pipefd[1], buf, cnt); printf("pid: %d, send %d bytes ", getpid(), cnt); } void sig_int(int signo){ printf("pid: %d, sig=%d ", getpid(), signo); signal(SIGINT, SIG_DFL); alarm(2); } int main(){ pid_t pid; char buf[BUF_SIZE]; int cnt = 0; if (pipe(pipefd) < 0) { perror("pipe error"); exit(EXIT_FAILURE); } if ((pid = fork()) < 0) { perror("fork error"); exit(EXIT_FAILURE); } else if (pid == 0) { signal(SIGALRM, sig_alrm); signal(SIGINT, sig_int); alarm(2); while (1) { printf("...child is waiting "); fflush(stdout); sleep(1); } } else { printf("parent pid: %d ", getpid()); fflush(stdout); close(pipefd[1]); while (1) { int n = read(pipefd[0], buf, 8); if (n <= 0) break; cnt += n; printf("receive %d bytes, %s ",n, buf); fflush(stdout); } printf("pid: %d, send SIGINT ", getpid()); fflush(stdout); kill(pid, SIGINT); sleep(1); printf("pid: %d, send SIGINT again ", getpid()); fflush(stdout); kill(pid, SIGINT); sleep(1); wait(NULL); printf("...child is waiting "); fflush(stdout); exit(EXIT_SUCCESS); } return 0; } 为什么该代码运行结果最后一次两个字符却取了八个字符，并且...child is waiting一直循环不止，该如何更改代码才能得到parentpid:221...childiswaiting...childiswaitingpid:222,sig=14send26bytesreceive8bytes,abcdefgh...childiswaitingreceive8bytes,ijklmnopreceive8bytes,qrstuvwxreceive2bytes,yzpid:222,sig=2...childiswaiting的运行结果。

前6行程序输出。 C/C++ #include <stdio.h> #include <stdlib.h> #include <sys/types.h> #include <unistd.h> #include <signal.h>

第一个头文件<stdio.h>提供了标准输入输出函数，第二个头文件<stdlib.h>提供了一些常用的函数和类型定义，第三个头文件<sys/types.h>定义了系统调用所需的数据类型，第四个头文件<unistd.h>提供了一些通用的系统服务...

#include #include<stdlib.h> #include <stdio.h> #include <sys/types.h> #include<signal.h> #include <unistd.h> void func () ; int main (void *arg) { int i,j; signal (17,func); int iPID=fork () ; if(iPID>0){ printf("PID:%d,Parent: Signal 17 will_be send to Child! " , getpid()) ; kill(iPID,17) ; printf ( "PID:%d, Parent: finished! " , getpid() ); } else { printf ( "PID:%d " , getpid()); sleep (1); printf ("PID:%d, Child: finished ! " , getpid()); exit (0); } return 0; } void func ( ) { printf("PID:%d,It is signal 17 processing function! " , getpid() ) ; }

如果 iPID>0，则表示当前进程是父进程，它会打印出自己的进程 ID（PID），然后向子进程发送信号 17。接着父进程会打印出自己的进程 ID 并结束。如果 iPID=0，则表示当前进程是子进程，它会打印出自己的进程 ID，...

#include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> #include <stdio.h> #include <string.h> #include #include <signal.h> #include <stdlib.h> static int fd; /* * ./doorbell /dev/sr501 */ int main(int argc, char **argv) { /* 1. 判断参数 / if (argc != 2) { printf("Usage: %s <dev>\n", argv[0]); return -1; } / 2. 打开文件 */ fd = open(argv[1], O_RDWR); if (fd == -1) { printf("can not open file %s\n", argv[1]); return -1; } int val; while (1) { if (read(fd, &val, 4) == 4) { printf("get value: 0x%x\n", val); if (val == 0X100) { printf("*****************"); system("aplay /music/welcome.wav"); } } else printf("get value error\n"); } close(fd); return 0; } 这是ALSA音频实验的APP模块，请帮我把轮询模式更改为异步模式

#include <alsa/asoundlib.h> #include <sys/epoll.h> void play_welcome_sound() { // ALSA PCM设备初始化 snd_pcm_t *pcm_handle; snd_pcm_open(&pcm_handle, "default", SND_PCM_STREAM_PLAYBACK, 0); // .....

#include <signal.h> #include <stdio.h> #include <unistd.h> #include <stdlib.h> void sigintTest(int sign_no) { printf("\nI have get SIGINT\n"); } void sigQuitTest(int sign_no) { printf("\nI have get SIGQUIT\n"); exit(0); } int main() { printf("Waiting for signal SIGINT \n "); signal(SIGINT, sigintTest); signal(SIGQUIT,sigQuitTest); pause(); while(1) { printf("I am running.\n"); sleep(1); } printf("bye.\n"); exit(0); }

在 main() 函数中，先输出一条等待信号的提示信息，然后使用 signal() 函数分别将 SIGINT 和 SIGQUIT 信号的处理函数注册到信号处理表中。接着调用 pause() 函数使程序挂起等待信号的到来，一旦收到信号，...

用signal函数改写下面的程序，使闹钟时间到后输出“ling ling ling”，然后接着执行pause()后的语句。提示：定时器时间到后向进程发出SIGALRM信号。 #include <unistd.h> #include <stdio.h> #include <stdlib.h> int main() { /* 调用alarm定时器函数 */ int ret = alarm(5); pause(); printf("I have been waken up.\n"); return 0; }

#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <signal.h> void alarm_handler(int sig) { printf("ling ling ling\n"); } int main() { // 注册SIGALRM信号处理函数 signal(SIGALRM, ...

详细分析以下代码#include <stdio.h> #include <signal.h> #include <unistd.h> #include<stdlib.h> #include<sys/wait.h> // 声明函数 func int func(); // 处理信号 17 的函数 int func() { printf("It is signal 17 processing function!\n"); // 添加分号 return 0; } int main() { int i,j; // 注册信号处理函数 // signal(17, func); signal(17, (__sighandler_t)func); if(i=fork()) { printf("Parent: Signal 17 will be sent to Child!\n"); // 向子进程发送信号 17 kill(i,17); wait(0); printf("Parent: finished!\n"); } else { // 子进程休眠 10 秒 sleep(10); printf("Child: A signal from my Parent is received!\n"); exit(0); } }

#include <stdio.h> #include <signal.h> #include <unistd.h> #include <stdlib.h> #include <sys/wait.h> 这些头文件包含了信号处理函数和进程通信相关的函数。 2. 声明函数 func int func(); ...

// >>> common include #include <iostream> #include <stdio.h> #include <stdlib.h> #include <signal.h> #include <unistd.h> // >>> verilator #include <memory> #include <verilated.h> #include <verilated_vcd_c.h> #include "VA_top.h" #include "sdm_config.h" #include "Sdm_node_A.h" using HW =VA_top; uint64_t GlobalMainTime = 0; int main(int argc, char argv, charenv) { const std::unique_ptr<VerilatedContext> contextp{new VerilatedContext}; const std::unique_ptr<HW> hw {new HW{contextp.get(), "TOP"}}; Sdm_config * shuncfg_ptr = new Sdm_config (sub_node_A_node_name); shuncfg_ptr->arg_parse (argc, argv); Sdm_node_A shunobj (shuncfg_ptr, hw.get(), contextp.get()); Verilated::mkdir("node_node_A_logs"); contextp->debug(0); contextp->randReset(2); contextp->commandArgs(argc, argv); #if VM_TRACE == 1 VerilatedVcdC* tgp = NULL; const char* flag = Verilated::commandArgsPlusMatch("trace"); if (flag && 0 ==strcmp(flag, "+trace")) { Info("Enter Trace!"); contextp->traceEverOn(true); tfp = new VerilatedVcdC; hw->trace(tfp,99); shunobj.fulleval(); std::string filename = shuncfg_ptr->dumpfile(); tfp->open(filename.c_str()); }; #endif shunobj.setup(); bool retmp; int loop = 0; while(1) { //Info("loop %d", loop); shunobj.update(); if (shunobj.finish()) break; do { shunobj.eval(); shunobj.sync(); } while(!shunobj.converge()); #if VM_TRACE == 1 if (flag && 0 == strcmp(flag, "+trace")) { tfp->dump(contextp->time()); } #endif loop++; } hw->final(); return 0; #if VM_TRACE == 1 if (flag && 0 == strcmp(flag, "+trace")){ tfp->close(); } #endif #if VM_COVERAGE Verilated::mkdir("node_node_A_logs"); contextp->coverageep()->write("node_node_A_logs/coverage.dat"); #endif }

这是一个C++程序的主函数，它使用Verilator来模拟硬件电路。程序的作用是模拟一个名为"Sdm_node_A"的硬件节点，并根据节点的配置进行操作。程序的主要流程如下： 1. 创建VerilatedContext和Verilated块的实例。...

#include <stdio.h> #include <stdlib.h> #include <string.h> #include #include <sys/time.h> #include <unistd.h> #include #include <signal.h> #include #include <algorithm> #include <iostream> #include <map> #include <string> #include <queue> #include <vector> #include <sstream> #define LOG_BRASERO_NUM 15 using namespace std; static char g_cpBrasero[] = { (char ) "ID", (char ) "刻录时间", (char ) "刻录机型号", (char ) "光盘属性", (char ) "刻录状态", (char ) "计算机帐户", (char ) "文件名称", (char ) "文件大小", (char ) "文件类型", (char ) "测试1", (char ) "测试2", (char ) "测试3", (char ) "测试4", (char ) "测试5", (char ) "测试6", }; typedef struct _tagBraseroLog { char cpValue[1024]; } BRASEROLOG; int uosaarch_line_parse(char pBuffer) { int index, len,lastLen; int ret = 0; char begin = NULL; char end = NULL; char lastEnd = NULL; //debug printf("进入了扫描"); BRASEROLOG BraseroLog[LOG_BRASERO_NUM]; memset(&BraseroLog, 0, LOG_BRASERO_NUM * sizeof(BRASEROLOG)); for (index = 0; index < LOG_BRASERO_NUM; index++) { begin = strstr(pBuffer, g_cpBrasero[index]); if(NULL == begin) continue; begin=strstr(begin,"="); end = strstr(pBuffer, g_cpBrasero[index + 1]); //end--; if (begin != NULL) { len = strlen("="); unsigned long strSize = end - begin - len ; printf("BraseroLOg[%d]=%s\n",index,BraseroLog[index].cpValue); //strncpy(BraseroLog[index].cpValue, begin + len, std::min(strSize, sizeof(BraseroLog[index].cpValue) - 1))； // printf("PrintLog[%d] = %s\n",index,BraseroLog[index].cpValue); } return 0; } return 1; } int main(){ char a[500] = "ID=1689309873, 刻录时间=2023-07-14 12:44:34, 刻录机型号=TSSTcorp-CDDVDW-SE-218CB-R95M6YMDA00008, 光盘属性=DVD+R, 刻录状态=成功, 计算机帐户=hba, 文件名称=/home/hba/Desktop/刻录测试文件.txt, 文件大小=66 B, 文件类型=文档"; uosaarch_line_parse(a); return 0; }

但是你没有在代码开头包含 <stdio.h> 头文件，所以编译器会发出警告。你需要在开头包含 <stdio.h> 头文件来解决这个问题。 2. 在 uosaarch_line_parse 函数中，你使用了 strstr 函数来查找字符串中的子字符...

在主函数的最开始会初始化一个全部变量 g_i4event 为 0。本关的编程任务是补全右侧代码片段中两段Begin至End中间的代码，具体要求如下：在 do _signal中分别为信号 SIGUSR1 、 SIGUSR2 注册信号处理函数 funcA 和 funcB ，而后将 g_i4event 置为 1；完成两个信号处理函数，其中 funcA 中将 g_i4event 置为 2， funcB 中将 g_i4event 为 3。#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <signal.h> int g_i4event; typedef void (sighandler_t)(int); /Begin/ /实现funcA和funcB*/ /*****End/ int do_signal(void) { /Begin/ /End*****/ }

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <signal.h> int g_i4event; typedef void (*sighandler_t)(int); void funcA(int signum) { g_i4event = 2; } void...

将下面代码修改正确#include <sys/types.h> # include<stdio.h> # include<signal.h> #include <unistd.h> #include <stdlib.h> #include void waiting(); void stop(); int main(void) { int p1, p2; signal(SIGINT, stop); while ((p1 = fork()) == -1); if (p1 > 0) /* In Parent Process/ { /(1) / while ((p2 = fork()) == -1); if (p2 > 0) /in parent process/ { / (2) / wait_mark = 1; waiting(0); kill(p1, 10); kill(p2, 12); wait(); wait(); printf("parent process is killed!\n"); exit(0); } else { /In Child Process 2/ wait_mark = 1; signal(12, stop); waiting(); lockf(1, 1, 0); printf("child process 2 is killed by parent!\n"); lockf(1, 0, 0); exit(0); } } else { /In Child Process 1*/ wait_mark = 1; signal(10, stop); waiting(); lockf(1, 1, 0); printf("child process 1 is killed by parent!\n"); lockf(1, 0, 0); exit(0); } return 0; } void waiting() { while (wait_mark != 0); } void stop() { wait_mark = 0; }

#include <stdio.h> #include <signal.h> #include <unistd.h> #include <stdlib.h> #include <sys/wait.h> int wait_mark = 0; void waiting(); void stop(); int main(void) { int p1, p2; signal(SIGINT, ...

#include <stdio.h> #include <string.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include #include <stdlib.h> #include <unistd.h> #include <netinet/ip.h> #define IP "127.0.0.1" #define PORT 8080 #define MAX 100 int final=0; // 创建socket套接字文件，并连接 // 接受数据 client 客户端 typedef struct sockaddr_in SIN; typedef struct sockaddr SA; SIN ser_addr; int sockfd; void message(void arg) { printf("thread creat success!\n"); char buf[100]; int signal; while(1) { if(final==1) break; memset(buf,0,100); signal=recv(sockfd,buf,MAX,0); if(signal!=0){ system("date"); write(1,buf,strlen(buf)); memset(buf,0,100);} } pthread_exit(NULL); } int main(int argc,char argv[]) { //1、创建套接字文件，返回套接字文件描述符 socket() sockfd=socket(AF_INET, SOCK_STREAM, 0); pthread_t tid; if(sockfd == -1) { perror("socket create failure\r\n"); return 0; } //2、创建结构，初始化数据 struct sockaddr 使用 struct sockaddr_in SIN ser_addr; ser_addr.sin_family = AF_INET;//选择ipv4协议族 ser_addr.sin_port=htons(PORT); //端口号要转换端绪，从小端绪转换从大端绪 ser_addr.sin_addr.s_addr=inet_addr(IP);//十进制的字符ip转换成网端数据格式服务端IP int len=sizeof(ser_addr); if(connect(sockfd,(SA )&ser_addr,len)==-1) { perror("connect failure\r\n"); return 0; }else { printf("WELCOME TO DADONG TALK ROOM!\r\n"); printf("Please sign you name:"); char temp[20]={0}; memset(temp,0,100); scanf("%s",temp); send(sockfd,temp,strlen(temp),0);//发送信息 pthread_create(&tid,NULL,message,NULL); } char wbuf[100]={0}; while(1) { memset(wbuf,0,100); read(0,wbuf,100); if(strncmp(wbuf,"quit",4)==0) { send(sockfd,wbuf,strlen(wbuf),0); final=1; close(sockfd); return 0; } send(sockfd,wbuf,strlen(wbuf),MSG_NOSIGNAL); memset(wbuf,0,100); usleep(20); } close(sockfd); return 0; } 请用中文帮我解释这些代码

这段代码是一个简单的基于Socket的聊天室程序。让我来解释一下每个部分的功能： 1. 头文件和变量定义：开始部分包含了一些标准库和网络相关的头文件，以及一些全局变量的定义。 2. 结构体定义：定义了两个结构体，...

详细分析以下代码#include <stdio.h> #include <signal.h> #include <unistd.h> #include <stdlib.h> #include <sys/wait.h> int pid1, pid2; int endflag = 0, pf1 = 0, pf2 = 0; void intdelete() { kill(pid1, 16); kill(pid2, 17); endflag = 1; } void int1() { printf("child process 1 is killed by parent!\n"); exit(0); } void int2() { printf("child process 2 is killed by parent!\n"); exit(0); } int main() { int exitpid; signal(SIGINT, SIG_IGN); signal(SIGQUIT, SIG_IGN); while ((pid1 = fork()) == -1); if (pid1 == 0) { printf("p1\n"); signal(SIGUSR1, int1); signal(16, SIG_IGN); pause(); exit(0); } else { while ((pid2 = fork()) == -1); if (pid2 == 0) { printf("p2\n"); signal(SIGUSR2, int2); signal(17, SIG_IGN); pause(); exit(0); } else { printf("parent\n"); signal(SIGINT, intdelete); /接收DEL信号，并转intdelete()/ waitpid(-1, &exitpid, 0); printf("parent process is killed!\n"); exit(0); } } }

这段代码是一个使用了信号处理的进程控制程序。程序中创建了两个子进程pid1和pid2，并且在父进程中对这两个子进程进行了控制。程序中使用了信号处理函数来控制子进程的运行和退出。当父进程接收到SIGINT信号时，会...

#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #include <signal.h> #include <fcntl.h> #include <time.h> #define TIMER_FILE "shijian.txt" #define PID_FILE "daemon.pid" static int running = 1; static int shijian_fd; int main(int argc, char *argv[]) { pid_t pid; pid = fork(); if (pid < 0) { printf("Daemon creation failed\n"); exit(1); } if (pid == 0) { time_t qTime= time(NULL); int pid_fd = open(PID_FILE, O_CREAT | O_RDWR, 0644); if (pid_fd < 0) { perror("Error opening pid file"); exit(EXIT_FAILURE); } if (flock(pid_fd, LOCK_EX | LOCK_NB) < 0) { fprintf(stderr, "Another instance is running\n"); exit(EXIT_FAILURE); } char pid_str[16]; int len = sprintf(pid_str, "%d", getpid()); if (write(pid_fd, pid_str, len) != len) { perror("Error writing pid file"); exit(EXIT_FAILURE); } shijian_fd = open(TIMER_FILE, O_CREAT | O_WRONLY | O_TRUNC, 0644); if (shijian_fd < 0) { perror("Error creating timer file"); exit(EXIT_FAILURE); } if (setsid() < 0) { printf("Background session creation failed\n"); exit(1); } void sigint_handler(int sig) { running = 0; } signal(SIGINT, sigint_handler); while (running) { char rTime[64]; sprintf(rTime, "%ld\n", time(NULL) - qTime+ 1); if (write(shijian_fd, rTime, strlen(rTime)) != strlen(rTime)) { perror("Error writing timer file"); exit(EXIT_FAILURE); } sleep(1); } close(shijian_fd); unlink(PID_FILE); } if (pid > 0){ printf("The ID of the child process is %d\n",pid); } return 0; }优化以上代码，并且重复率降低

#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #include <signal.h> #include <fcntl.h> #include <time.h> #define TIMER_FILE "shijian.txt" #define PID_FILE ...

按每一行解释如下代码：#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/types.h> #include <sys/wait.h> #include <sys/ipc.h> #include <sys/sem.h> #include <time.h> #define MSG_SIZE 100 struct sembuf sem_wait = {0, -1, SEM_UNDO}; struct sembuf sem_signal = {0, 1, SEM_UNDO}; int pfd[2]; int semid; void send_msg(int id) { srand(time(NULL) + id); int len = rand() % MSG_SIZE + 1; char msg[len]; for (int i = 0; i < len; i++) { msg[i] = 'A' + rand() % 26; } msg[len - 1] = '\0'; printf("Child %d sends message: %s\n", id, msg); semop(semid, &sem_wait, 1); write(pfd[1], msg, strlen(msg) + 1); semop(semid, &sem_signal, 1); } int main() { if (pipe(pfd) == -1) { perror("pipe"); exit(EXIT_FAILURE); } semid = semget(IPC_PRIVATE, 1, IPC_CREAT | 0666); if (semid == -1) { perror("semget"); exit(EXIT_FAILURE); } if (semctl(semid, 0, SETVAL, 1) == -1) { perror("semctl"); exit(EXIT_FAILURE); } for (int i = 0; i < 3; i++) { pid_t pid = fork(); if (pid == -1) { perror("fork"); exit(EXIT_FAILURE); } else if (pid == 0) { send_msg(i); exit(EXIT_SUCCESS); } } for (int i = 0; i < 3; i++) { wait(NULL); } char msg[MSG_SIZE]; int total_bytes = 0; while (total_bytes < MSG_SIZE * 3) { semop(semid, &sem_wait, 1); int n_bytes = read(pfd[0], msg + total_bytes, MSG_SIZE * 3 - total_bytes); if (n_bytes == -1) { perror("read"); exit(EXIT_FAILURE); } total_bytes += n_bytes; semop(semid, &sem_signal, 1); } printf("Parent receives message: %s\n", msg); close(pfd[0]); close(pfd[1]); if (semctl(semid, 0, IPC_RMID) == -1) { perror("semctl"); exit(EXIT_FAILURE); } return 0; }

#include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/types.h> #include <sys/wait.h> #include <sys/ipc.h> #include <sys/sem.h> #include <time.h> 2. 定义宏 ...

解释#include <stdio.h> #include <signal.h> #include <unistd.h> #include <stdlib.h> void waiting(), stop(); int wait_mark; int main() { int p1, p2; signal(SIGINT, stop); while ((p1 = fork()) == -1); if (p1 > 0) { while ((p2 = fork()) == -1); if (p2 > 0) { wait_mark = 1; waiting(0); kill(p1, 10); kill(p2, 12); wait(); wait(); printf("Parent process is killed!\n"); exit(0); } else { wait_mark = 1; signal(12, stop); waiting(); lockf(1, 1, 0); printf("Child process 2 is killed by parent!\n"); lockf(1, 0, 0); exit(0); } } else { wait_mark = 1; signal(10, stop); waiting(); lockf(1, 1, 0); printf("Child process 1 is killed by parent!\n"); lockf(1, 0, 0); exit(0); } } void waiting() { while (wait_mark != 0); } void stop() { wait_mark = 0; }

程序中包含了四个头文件：stdio.h、signal.h、unistd.h和stdlib.h。程序中定义了两个函数waiting()和stop()，分别用于进程等待和停止等待。同时定义了一个全局变量wait_mark，用于标记进程是否等待。在主函数中...

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