在Linux系统中,C++可以通过多种方式实现进程间通信(IPC)。以下是一些常用的IPC机制:
管道(Pipes):
信号(Signals):
消息队列(Message Queues):
共享内存(Shared Memory):
信号量(Semaphores):
套接字(Sockets):
下面是一些简单的示例代码,展示了如何在C++中使用这些IPC机制:
#include <unistd.h>
#include <iostream>
int main() {
int pipefd[2];
char buffer[256];
// 创建管道
if (pipe(pipefd) == -1) {
perror("pipe");
return EXIT_FAILURE;
}
// 父进程关闭写端,读端留给子进程
close(pipefd[1]);
// 子进程关闭读端,写端留给父进程
close(pipefd[0]);
// 子进程向管道写入数据
const char* message = "Hello from child!";
write(pipefd[1], message, strlen(message) + 1);
// 父进程从管道读取数据
read(pipefd[0], buffer, sizeof(buffer));
std::cout << "Parent received: " << buffer << std::endl;
// 关闭管道
close(pipefd[0]);
close(pipefd[1]);
return EXIT_SUCCESS;
}
#include <sys/ipc.h>
#include <sys/shm.h>
#include <iostream>
#include <cstring>
int main() {
key_t key = ftok("shmfile", 65);
int shmid = shmget(key, 1024, 0666|IPC_CREAT);
char *str = (char*) shmat(shmid, (void*)0, 0);
if (str == (char*)(-1)) {
perror("shmat");
return EXIT_FAILURE;
}
strcpy(str, "Hello World");
std::cout << "String in memory: " << str << std::endl;
shmdt(str);
shmctl(shmid, IPC_RMID, NULL);
return EXIT_SUCCESS;
}
#include <sys/ipc.h>
#include <sys/sem.h>
#include <iostream>
union semun {
int val;
struct semid_ds *buf;
unsigned short *array;
};
int main() {
key_t key = ftok("semfile", 65);
int semid = semget(key, 1, 0666|IPC_CREAT);
union semun arg;
arg.val = 1; // 初始化信号量为1
semctl(semid, 0, SETVAL, arg);
// 使用信号量进行P操作(等待)
struct sembuf sb = {0, -1, SEM_UNDO};
semop(semid, &sb, 1);
std::cout << "Semaphore value after P operation: " << semctl(semid, 0, GETVAL, arg) << std::endl;
// 使用信号量进行V操作(释放)
sb.sem_op = 1;
semop(semid, &sb, 1);
std::cout << "Semaphore value after V operation: " << semctl(semid, 0, GETVAL, arg) << std::endl;
semctl(semid, 0, IPC_RMID);
return EXIT_SUCCESS;
}
请注意,这些示例仅用于演示目的,实际应用中可能需要更复杂的错误处理和同步机制。在使用这些IPC机制时,还需要确保正确地处理权限和安全性问题。