ipc 相关问题

IPC代表进程间通信，代表一组在线程和进程之间交换数据和消息的方法。

Android IPC Binder - onTransact() 等待前一个返回

我有一个使用 IPC 的应用程序。我的主应用程序正在接收来自远程服务的单向回调。收到这些回调后，我正在做一些及时的工作（1-20 秒）。如果我明白

android ipc android-binder

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操作系统学校项目

我需要帮助使用 C 和系统调用在 Ubuntu 中完成我的 schhol 项目。该项目的目的是模拟船舶在港口之间运输不同种类货物的交通

c linux ipc system-calls

回答 0 投票 0

亲子沟通问题

父母有“m”条消息要发送给“n”个孩子。在每次迭代中，它向所有子节点发送一条消息。如果所有回复“已收到”，它会发送下一条消息。下面是我的代码 #包括父母有“m”条消息要发送给“n”个孩子。在每次迭代中，它向所有子节点发送一条消息。如果所有回复“已收到”，它会发送下一条消息。下面是我的代码 #include <sys/types.h> #include <sys/ipc.h> #include <sys/msg.h> #include <sys/wait.h> #include <stdio.h> #include <string.h> #include <signal.h> #include <stdlib.h> #include <unistd.h> #define MAX_LEN 50 struct details { int no; int id; char msg_text[MAX_LEN]; }; typedef struct msg_buf { long int msg_type; struct details d; } msg; char message[20][50] = { " ", "Message1", "Message2", "Message3", "Message4", "Message5", "Message6", "Message7", "Message8" }; int main(int argc, char *argv[]) { int id1, id2, n, m, i, j, status, p_id; pid_t pid; msg snd, rcvd; if (argc < 2) { perror("Too few arguments"); return -1; } n = atoi(argv[1]); m = atoi(argv[2]); id1 = msgget((key_t)78, IPC_CREAT | 0666); id2 = msgget((key_t)56, IPC_CREAT | 0666); if (id1 == -1 || id2 == -1) { printf("Error in creating message queue\n"); return -1; } p_id = getpid(); printf("\nQueues are created.\n\n"); for (i = 1; i <= n; i++) { pid = fork(); if (pid == 0) break; } if (pid == 0) { for (j = 1; j <= m; j++) { printf("Process %d waiting for message %d\n", getpid(), j); while (msgrcv(id1, &rcvd, sizeof(struct details), j + 1, IPC_NOWAIT) < 0) { } srand(time(0)); strcpy(snd.d.msg_text, "Received"); snd.msg_type = rcvd.msg_type; snd.d.no = rcvd.d.no; snd.d.id = getpid(); if (msgsnd(id2, &snd, sizeof(struct details), IPC_NOWAIT) < 0) { perror("msgsnd"); } else { printf("Reply sending successful for message %d for process %d\n", snd.d.no, snd.d.id); } } } if (p_id == getpid()) { for (j = 1; j <= m; j++) { strcpy(snd.d.msg_text, message[j]); snd.msg_type = j + 1; snd.d.no = j; if (msgsnd(id1, &snd, sizeof(struct details), 0) < 0) { perror("msgsnd"); } else { printf("Message %d sent- \t\t\t\t%s\n", j, snd.d.msg_text); } for (i = 1; i <= n; i++) { sleep(i); if (msgrcv(id2, &rcvd, sizeof(struct details), j + 1, 0) >= 0) { printf("Reply received from child %d for message %d - \t%s\n", rcvd.d.id, j, rcvd.d.msg_text); } } } wait(NULL); printf("Communication End.\n\n"); } } 我得到的输出是n=2，m=2是： Queues are created. Message 1 sent- Message1 Process 14804 waiting for message 1 Process 14805 waiting for message 1 Reply sending successful for message 1 for process 14804 Process 14804 waiting for message 2 Reply received from child 14804 for message 1 - Received 此后什么也没有打印。没有任何进展。问题是什么？如何解决这个问题？最大的单一问题是在评论中提到的一个： AFAICS，您每次迭代发送一条消息，因此最多一个孩子可以阅读它。您不会向每个孩子发送一条消息。任何给定的消息都可以被（最多）一个进程接收。对于 n 进程接收消息，您必须发送 n 消息。其他问题主要是装饰性的。我使用了 GitHub 上我的 SOQ（堆栈溢出问题）存储库中可用的日志记录代码作为文件 stderr.c 和 stderr.h 在 src/libsoq 子目录中。一些消息被写入 stdout — 没有只接受文件流的函数，所以我使用 err_logmsg() 接受文件流、控制选项和退出状态（但函数不应该退出，所以这是未使用的）以及格式和参数。结果是： /* SO 7592-2454 */ #include <errno.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/ipc.h> #include <sys/msg.h> #include <sys/wait.h> #include <unistd.h> #include "stderr.h" #define MAX_LEN 50 struct details { int no; int id; char msg_text[MAX_LEN]; }; typedef struct msg_buf { long int msg_type; struct details d; } msg; static char message[20][50] = { " ", "Message1", "Message2", "Message3", "Message4", "Message5", "Message6", "Message7", "Message8" }; static const char usestr[] = "num_kids num_msgs"; static void dump_message(const char *tag, const msg *info) { err_logmsg(stdout, err_getlogopts(), 0, "%s: type %ld (details: no %d, id %d, text [%s])\n", tag, info->msg_type, info->d.no, info->d.id, info->d.msg_text); } int main(int argc, char *argv[]) { err_setarg0(argv[0]); if (argc != 3) err_usage(usestr); int n = atoi(argv[1]); int m = atoi(argv[2]); int id1 = msgget((key_t)78, IPC_CREAT | 0666); int id2 = msgget((key_t)56, IPC_CREAT | 0666); if (id1 == -1 || id2 == -1) err_syserr("failed to create a message queue: "); pid_t p_id = getpid(); err_setlogopts(ERR_PID|ERR_MILLI); err_logmsg(stdout, err_getlogopts(), 0, "Queues are created.\n"); pid_t pid; for (int i = 1; i <= n; i++) { pid = fork(); if (pid == 0) break; } msg snd; msg rcvd; if (pid == 0) { for (int j = 1; j <= m; j++) { err_logmsg(stdout, err_getlogopts(), 0, "Waiting for message %d\n", j); while (msgrcv(id1, &rcvd, sizeof(struct details), j + 1, IPC_NOWAIT) < 0) err_syserr("msgrcv() returned with error status: "); dump_message("Message received", &rcvd); strcpy(snd.d.msg_text, "Received"); snd.msg_type = rcvd.msg_type; snd.d.no = rcvd.d.no; snd.d.id = getpid(); if (msgsnd(id2, &snd, sizeof(struct details), IPC_NOWAIT) < 0) err_sysrem("msgsnd() failed: "); else dump_message("Message sent", &snd); } err_logmsg(stdout, err_getlogopts(), 0, "Child process complete\n"); exit(EXIT_SUCCESS); } if (p_id == getpid()) { for (int j = 1; j <= m; j++) { strcpy(snd.d.msg_text, message[j]); snd.msg_type = j + 1; snd.d.no = j; for (int i = 0; i < n; i++) { if (msgsnd(id1, &snd, sizeof(struct details), 0) < 0) err_sysrem("msgsnd() failed: "); else dump_message("Message sent", &snd); } for (int i = 1; i <= n; i++) { err_logmsg(stdout, err_getlogopts(), 0, "Dozing for %d seconds\n", i); sleep(i); if (msgrcv(id2, &rcvd, sizeof(struct details), j + 1, 0) >= 0) dump_message("Reply received", &rcvd); else err_syserr("msgrcv() failed: "); } } int corpse; int status; while ((corpse = wait(&status)) > 0) err_remark("Child %d exited with status 0x%.4X\n", corpse, status); err_logmsg(stdout, err_getlogopts(), 0, "Communication End.\n\n"); } return 0; } 有大量的日志记录，因为我需要看看发生了什么。代码应该验证 n 和 m 的值（它们应该至少是 1 并且不超过一些微弱的理智数字（例如 10，但会有一个或两个值（枚举或定义常数）来限制可接受的范围。这是一个示例输出（源代码msg79.c，程序msg79）： $ ./msg79 2 3 msg79: 2023-04-03 21:36:38.215 - pid=67247: Queues are created. msg79: 2023-04-03 21:36:38.217 - pid=67247: Message sent: type 2 (details: no 1, id 1, text [Message1]) msg79: 2023-04-03 21:36:38.217 - pid=67247: Message sent: type 2 (details: no 1, id 1, text [Message1]) msg79: 2023-04-03 21:36:38.217 - pid=67247: Dozing for 1 seconds msg79: 2023-04-03 21:36:38.217 - pid=67248: Waiting for message 1 msg79: 2023-04-03 21:36:38.217 - pid=67249: Waiting for message 1 msg79: 2023-04-03 21:36:38.217 - pid=67248: Message received: type 2 (details: no 1, id 1, text [Message1]) msg79: 2023-04-03 21:36:38.217 - pid=67249: Message received: type 2 (details: no 1, id 1, text [Message1]) msg79: 2023-04-03 21:36:38.217 - pid=67248: Message sent: type 2 (details: no 1, id 67248, text [Received]) msg79: 2023-04-03 21:36:38.217 - pid=67248: Waiting for message 2 msg79: 2023-04-03 21:36:38.217 - pid=67249: Message sent: type 2 (details: no 1, id 67249, text [Received]) msg79: 2023-04-03 21:36:38.218 - pid=67248: Message received: type 3 (details: no 2, id 1, text [Message2]) msg79: 2023-04-03 21:36:38.218 - pid=67249: Waiting for message 2 msg79: 2023-04-03 21:36:38.218 - pid=67249: Message received: type 3 (details: no 2, id 1, text [Message2]) msg79: 2023-04-03 21:36:38.218 - pid=67248: Message sent: type 3 (details: no 2, id 67248, text [Received]) msg79: 2023-04-03 21:36:38.218 - pid=67249: Message sent: type 3 (details: no 2, id 67249, text [Received]) msg79: 2023-04-03 21:36:38.218 - pid=67248: Waiting for message 3 msg79: 2023-04-03 21:36:38.219 - pid=67249: Waiting for message 3 msg79: 2023-04-03 21:36:38.219 - pid=67248: Message received: type 4 (details: no 3, id 1, text [Message3]) msg79: 2023-04-03 21:36:38.219 - pid=67249: Message received: type 4 (details: no 3, id 1, text [Message3]) msg79: 2023-04-03 21:36:38.219 - pid=67248: Message sent: type 4 (details: no 3, id 67248, text [Received]) msg79: 2023-04-03 21:36:38.219 - pid=67249: Message sent: type 4 (details: no 3, id 67249, text [Received]) msg79: 2023-04-03 21:36:38.219 - pid=67248: Child process complete msg79: 2023-04-03 21:36:38.219 - pid=67249: Child process complete msg79: 2023-04-03 21:36:39.219 - pid=67247: Reply received: type 2 (details: no 1, id 67248, text [Received]) msg79: 2023-04-03 21:36:39.219 - pid=67247: Dozing for 2 seconds msg79: 2023-04-03 21:36:41.220 - pid=67247: Reply received: type 2 (details: no 1, id 67249, text [Received]) msg79: 2023-04-03 21:36:41.220 - pid=67247: Message sent: type 3 (details: no 2, id 1, text [Message2]) msg79: 2023-04-03 21:36:41.220 - pid=67247: Message sent: type 3 (details: no 2, id 1, text [Message2]) msg79: 2023-04-03 21:36:41.220 - pid=67247: Dozing for 1 seconds msg79: 2023-04-03 21:36:42.221 - pid=67247: Reply received: type 3 (details: no 2, id 67248, text [Received]) msg79: 2023-04-03 21:36:42.221 - pid=67247: Dozing for 2 seconds msg79: 2023-04-03 21:36:44.223 - pid=67247: Reply received: type 3 (details: no 2, id 67249, text [Received]) msg79: 2023-04-03 21:36:44.223 - pid=67247: Message sent: type 4 (details: no 3, id 1, text [Message3]) msg79: 2023-04-03 21:36:44.223 - pid=67247: Message sent: type 4 (details: no 3, id 1, text [Message3]) msg79: 2023-04-03 21:36:44.223 - pid=67247: Dozing for 1 seconds msg79: 2023-04-03 21:36:45.227 - pid=67247: Reply received: type 4 (details: no 3, id 67248, text [Received]) msg79: 2023-04-03 21:36:45.227 - pid=67247: Dozing for 2 seconds msg79: 2023-04-03 21:36:47.227 - pid=67247: Reply received: type 4 (details: no 3, id 67249, text [Received]) msg79: 2023-04-03 21:36:47.227 - pid=67247: Child 67249 exited with status 0x0000 msg79: 2023-04-03 21:36:47.227 - pid=67247: Child 67248 exited with status 0x0000 msg79: 2023-04-03 21:36:47.228 - pid=67247: Communication End. $

c ipc message-queue

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如何使用消息队列在 C 中的进程之间获得随机暂停？

我正在编写一个使用进程间消息队列的 C 程序。我正在尝试重现进程 J（法官）和 n-child 进程之间的拍卖。程序从输入文件 txt 和 nu...

c ipc message-queue

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回复 webContents.send

我的理解是你不能从渲染进程回复从主进程发送的事件。当通信从渲染器进程到主进程时，你可以做同样的事情

javascript electron ipc

回答 1 投票 0

如何在 C 中使用进程间通信进行正确的消息队列？

我尝试在 C 中使用消息队列模拟宾果游戏。我的程序这样做：父亲应该分发孩子的卡片，而不是特定的顺序。孩子们收到卡片并将其打印在

c operating-system ipc

回答 1 投票 0

如何在守护进程中使用具有多个进程的单个命名管道 - Bash 中的客户端 IPC？

我正在尝试编写一个脚本来启动一个守护进程，该守护进程同时通过两个命名管道 $FIFO.out 和 $FIFO.in 分别传输其输出和输入。我想做的是给客户进程

bash pipe sh ipc fifo

回答 1 投票 0

如何在 Electron 中启动网络套接字并从 utilityProcess 发回数据

我正在尝试使用新的 utilityProcess 模块进行后台工作，而不是 Electron 中的隐藏渲染器。我似乎找不到任何好的例子。使用。该文档相当简洁。

javascript node.js electron ipc

回答 0 投票 0

ctrl c时如何删除共享内存？

我写了一个 shm 结构如下：类 ShmWorker { 民众： ShmWorker() = 默认值；虚拟 ~ShmWorker() { shmdt（m_data）； shmctl(shmid, IPC_RMID, 0); // 这就是问题所在...

c++ ipc shared-memory

回答 1 投票 0

如何在不同conda环境的两个不同python进程之间交换数据？

A 和 B 两个 python 脚本存在兼容性问题，需要为它们提供单独的 conda 环境。这是场景。当脚本 A 运行时，它向进程 B 发送数据（脚本 B 运行在一个

python ipc

回答 2 投票 0

在进程之间共享条件变量和互斥量：之前是否必须锁定互斥量？

我需要一些帮助来理解如何在 C 中使用条件变量来解决练习。这是一个小例子： #包括 #包括 #包括我需要一些帮助来理解如何在 C 中使用条件变量来解决练习。这是一个小例子： #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <pthread.h> #include <string.h> #include <errno.h> #include <sys/types.h> #include <sys/mman.h> #include <sys/stat.h> #include <fcntl.h> #define OKTOWRITE "/oktowrite" #define MESSAGE "/message" #define MUTEX "/lock" int main(int argc, char** argv) { pthread_cond_t* condition; pthread_mutex_t *mutex; char* message; int des_cond, des_msg, des_mutex; int mode = S_IRWXU | S_IRWXG; des_mutex = shm_open(MUTEX, O_CREAT | O_RDWR | O_TRUNC, mode); if (des_mutex < 0) { perror("failure on shm_open on des_mutex"); exit(1); } if (ftruncate(des_mutex, sizeof(pthread_mutex_t)) == -1) { perror("Error on ftruncate to sizeof pthread_cond_t\n"); exit(-1); } mutex = (pthread_mutex_t*) mmap(NULL, sizeof(pthread_mutex_t), PROT_READ | PROT_WRITE, MAP_SHARED, des_mutex, 0); if (mutex == MAP_FAILED ) { perror("Error on mmap on mutex\n"); exit(1); } pthread_mutex_init(mutex, NULL ); des_cond = shm_open(OKTOWRITE, O_CREAT | O_RDWR | O_TRUNC, mode); if (des_cond < 0) { perror("failure on shm_open on des_cond"); exit(1); } if (ftruncate(des_cond, sizeof(pthread_cond_t)) == -1) { perror("Error on ftruncate to sizeof pthread_cond_t\n"); exit(-1); } condition = (pthread_cond_t*) mmap(NULL, sizeof(pthread_cond_t), PROT_READ | PROT_WRITE, MAP_SHARED, des_cond, 0); if (condition == MAP_FAILED ) { perror("Error on mmap on condition\n"); exit(1); } pthread_cond_init(condition, NULL ); if (!fork()) { sleep(3); pthread_mutex_lock(mutex); pthread_cond_signal(condition); pthread_mutex_unlock(mutex); printf("son signaled\n"); exit(0); } else { printf("wait on condition\n"); pthread_mutex_lock(mutex); pthread_cond_wait(condition, mutex); pthread_mutex_unlock(mutex); printf("Signaled by son process, wake up\n"); pthread_mutex_destroy(mutex); pthread_cond_destroy(condition); shm_unlink(OKTOWRITE); shm_unlink(MESSAGE); shm_unlink(MUTEX); return 0; } } 问题是进程的父亲继续被锁定，即使在儿子发出信号之后也是如此。一切都在共享内存中（使用shm_open和mmap）所以两个进程的条件应该相同。在调用 wait 或 signal 之前锁定互斥锁可能是我犯了一个错误吗？编辑：感谢所有帮助过我的人。这是标有关键部分的正确代码： #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <pthread.h> #include <string.h> #include <errno.h> #include <sys/types.h> #include <sys/mman.h> #include <sys/stat.h> #include <fcntl.h> #define OKTOWRITE "/condwrite" #define MESSAGE "/msg" #define MUTEX "/mutex_lock" int main(int argc, char** argv) { pthread_cond_t* condition; pthread_mutex_t* mutex; char* message; int des_cond, des_msg, des_mutex; int mode = S_IRWXU | S_IRWXG; des_mutex = shm_open(MUTEX, O_CREAT | O_RDWR | O_TRUNC, mode); if (des_mutex < 0) { perror("failure on shm_open on des_mutex"); exit(1); } if (ftruncate(des_mutex, sizeof(pthread_mutex_t)) == -1) { perror("Error on ftruncate to sizeof pthread_cond_t\n"); exit(-1); } mutex = (pthread_mutex_t*) mmap(NULL, sizeof(pthread_mutex_t), PROT_READ | PROT_WRITE, MAP_SHARED, des_mutex, 0); if (mutex == MAP_FAILED ) { perror("Error on mmap on mutex\n"); exit(1); } des_cond = shm_open(OKTOWRITE, O_CREAT | O_RDWR | O_TRUNC, mode); if (des_cond < 0) { perror("failure on shm_open on des_cond"); exit(1); } if (ftruncate(des_cond, sizeof(pthread_cond_t)) == -1) { perror("Error on ftruncate to sizeof pthread_cond_t\n"); exit(-1); } condition = (pthread_cond_t*) mmap(NULL, sizeof(pthread_cond_t), PROT_READ | PROT_WRITE, MAP_SHARED, des_cond, 0); if (condition == MAP_FAILED ) { perror("Error on mmap on condition\n"); exit(1); } /* HERE WE GO */ /**************************************/ /* set mutex shared between processes */ pthread_mutexattr_t mutexAttr; pthread_mutexattr_setpshared(&mutexAttr, PTHREAD_PROCESS_SHARED); pthread_mutex_init(mutex, &mutexAttr); /* set condition shared between processes */ pthread_condattr_t condAttr; pthread_condattr_setpshared(&condAttr, PTHREAD_PROCESS_SHARED); pthread_cond_init(condition, &condAttr); /*************************************/ if (!fork()) { sleep(10); pthread_mutex_lock(mutex); pthread_cond_signal(condition); printf("son signaled\n"); pthread_mutex_unlock(mutex); exit(0); } else { printf("father waits on condition\n"); pthread_mutex_lock(mutex); pthread_cond_wait(condition, mutex); pthread_mutex_unlock(mutex); printf("Signaled by son process, wake up!!!!!!!!\n"); pthread_condattr_destroy(&condAttr); pthread_mutexattr_destroy(&mutexAttr); pthread_mutex_destroy(mutex); pthread_cond_destroy(condition); shm_unlink(OKTOWRITE); shm_unlink(MESSAGE); shm_unlink(MUTEX); } return 0; } 要在进程之间共享，需要通过正确初始化的属性相应地初始化互斥量：http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_mutexattr_setpshared.html #include <pthread.h> ... pthread_mutex_t * pmutex = NULL; pthread_mutexattr_t attrmutex; /* Initialise attribute to mutex. */ pthread_mutexattr_init(&attrmutex); pthread_mutexattr_setpshared(&attrmutex, PTHREAD_PROCESS_SHARED); /* Allocate memory to pmutex here. */ /* Initialise mutex. */ pthread_mutex_init(pmutex, &attrmutex); /* Use the mutex. */ /* Clean up. */ pthread_mutex_destroy(pmutex); pthread_mutexattr_destroy(&attrmutex); （为了本示例的可读性，省略了错误检查）这同样适用于应该在进程之间共享的条件变量：http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_condattr_setpshared.html #include <pthread.h> ... pthread_cond_t * pcond = NULL; pthread_condattr_t attrcond; /* Initialise attribute to condition. */ pthread_condattr_init(&attrcond); pthread_condattr_setpshared(&attrcond, PTHREAD_PROCESS_SHARED); /* Allocate memory to pcond here. */ /* Initialise condition. */ pthread_cond_init(pcond, &attrcond); /* Use the condition. */ /* Clean up. */ pthread_cond_destroy(pcond); pthread_condattr_destroy(&attrcond); （为了本示例的可读性，省略了错误检查）另请参阅此答案：https://stackoverflow.com/a/2390670/694576 等待一个条件之前应该有一个 while 语句，像这样： pthread_mutex_lock(mutex); while(!conditionSatisfied) pthread_cond_wait(condition, mutex); pthread_mutex_unlock(mutex); while 信号应该通过以下方式完成： pthread_mutex_lock(mutex); conditionSatisfied = true; pthread_cond_signal(condition); pthread_mutex_unlock(mutex); 是的，必须在pthread_cond_wait之前锁定互斥量，但不必为pthread_cond_signal锁定。如果你回头看看你的代码，你会发现互斥量将被解锁两次，这是错误的标志......孩子也有可能在已被父母破坏的互斥量上调用解锁...... 顺便说一下，睡眠并不能保证父进程会先执行。为了确保这一点，您将需要……一个条件变量……

c pthreads ipc mutex condition-variable

回答 3 投票 0

将 std::mutex 放在共享内存中是个好主意吗？

我想设计一个共享内存来在多个进程之间传递数据。在多线程中，我需要 pthread_mutex_t 来投影临界区。所以我想在...中分配一个 pthread_mutex_t

c++ multithreading pthreads ipc shared-memory

回答 0 投票 0

尝试在 Windows 10 中打开现有命名管道 - errno 22，无效参数，但为什么呢？

我正在编写/试验需要连接到 Windows 10 中现有命名管道的 python 脚本。我正在使用 Python 3.8。命名管道具体来说，我正在尝试连接到名为

python python-3.x pipe ipc named-pipes

回答 1 投票 0

UWP 服务器 - 进程间通信 - 技术选择

我们有一个 UWP（Microsoft Store 分布式）应用程序，我们的客户希望通过他的软件进行控制。主要目标是客户可以控制应用程序（就好像用户会进行交互