stdlib.h> #include <string.h> #include <fcntl.h> #include <sys/stat.h> #include <sys/types.h> #include <unistd.h> #define FIFO_PATH "/tmp/my_named_pipe" #define BUFFER_SIZE 256 int main() { int fd; char buffer[BUFFER_SIZE]; const char *message = "Hello from named pipe ...
{intpipe_fd;charbuffer[BUFFER_SIZE +1];//reset all bytes in buffer as '\0'memset(buffer,'\0',sizeof(buffer));//open FIFO pipe file.//this will be brocked until some one open another end point(write-point) of this pipepipe_fd =open(FIFO_NAME, O_RDONLY);if(read(pipe_fd, buffe...
chars_read = fread(buffer, sizeof(char), BUFSIZ, read_fp); } //Close the file stream pclose(read_fp); pclose(write_fp); exit(EXIT_SUCCESS); } exit(EXIT_FAILURE); } FIFO(named pipe)的创建 FIFO与pipe不同的是,每个FIFO有一个路径名与之关联,从而允许无亲缘关系的进程访问同一个FIFO。 FI...
进程等待管道文件,PCB会被放在文件的等待队列中,有数据之后会重新投入运行队列 ssize_t s = read(fds[0], buffer, sizeof buffer - 1); //-1是为了将读取到buffer的内容进行处理,预留一个位置放\0 std::cout << "BBBBBBBBBBBBBBBB" << std::endl; if (s > 0) { buffer[s] = 0; // 写入的...
char buf[MAXSIZE]; char x; short y; }; int main() { /*消息队列*/ mqd_t msgq_id; struct MsgType msg; unsigned int prio = 1; unsigned int send_size = BUFFER; struct mq_attr msgq_attr; const char *file = "/posix"; /*mq_open() for creating a new queue (using default attri...
// 读取文件intReadNamedPipe(std::string*out){char buffer[128];int n=read(_fd,buffer,sizeof(buffer));buffer[n]=0;*out=buffer;returnn;}// 写入文件intWriteNamedPipe(conststd::string&in){int n=write(_fd,in.c_str(),in.size());returnn;} ...
下面是父进程作为读取的通信代码,在调用read读取时,我们将读取的大小最大设置为sizeof buffer -1,这是为了在读取的数据超过缓冲区大小时,我们仍然能够在缓冲区中预留出最后一个位置放\0,这样做的目的其实是在读取时,将管道中的数据当作字符串来处理,所以我们会在读取到数据后,手动的在其末尾处添加\0,将其看作...
同时Linux也遵循IEEE制定的Posix IPC标准,在三者的基础之上实现了以下几种主要的IPC机制:管道(Pipe)及命名管道(Named Pipe),信号(Signal),消息队列(Message queue),共享内存(Shared Memory),信号量(Semaphore),套接字(Socket)。通过这些IPC机制,用户空间进程之间可以完成互相通信。为了完成内核空间与用户空间通信,Linux...
SYSCALL_DEFINE2(pipe2, int __user *, fildes, int, flags) { struct file *files[2]; int fd[2]; int error; error = __do_pipe_flags(fd, files, flags); if (!error) { if (unlikely(copy_to_user(fildes, fd, sizeof(fd))) { ....
semun arg: union semun { int val; /* Value for SETVAL */ struct semid_ds *buf; /* Buffer for IPC_STAT, IPC_SET */ unsigned short *array; /* Array for GETALL, SETALL */ struct seminfo *__buf; /* Buffer for IPC_INFO (Linux-specific) */ }; 返回值: 成功,消息队列ID,出错 ...