unix网络编程卷2：管道和FIFO

2019-11-10 16:44:59

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管道和FIFO

管道（Pipe）：管道可用于具有亲缘关系进程间的通信，允许一个进程和另一个与它有共同祖先的进程之间进行通信。命名管道（named pipe）：命名管道克服了管道没有名字的限制，因此，除具有管道所具有的功能外，它还允许无亲缘关系进程间的通信。命名管道在文件系统中有对应的文件名。命名管道通过命令mkfifo或系统调用mkfifo来创建。#include <unistd.h>int pipe（int fd[2]）

该函数返回两个文件描述符 fd[[0]和fdp[1],前者用于读，后者用于写。

#include <iostream>#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <sys/types.h>#include <sys/wait.h>#include <fcntl.h>#include <string.h>void client(int readfd, int writefd);void server(int readfd, int writefd);int main(int argc,char **argv){ int pipe1[2], pipe2[2]; int childpid; pipe(pipe1); pipe(pipe2); if( (childpid = fork()) == 0) //child { close(pipe1[1]); close(pipe2[0]); server(pipe1[0],pipe2[1]); exit(0); } close(pipe1[0]); close(pipe2[1]); client(pipe2[0],pipe1[1]); waitpid(childpid, NULL, 0); exit(0);}void server(int readfd, int writefd){ int fd; size_t n; char buff[4097]; if( (n = read(readfd, buff, 4096)) == 0) { std::cout<< "read file error " << std::endl; return; } buff[n] = '/0'; std::cout << "the server get filename from client:" << buff << std::endl; if( (fd = open(buff, O_RDONLY)) < 0) { std::cout << "the file file can't open file" << std::endl; write(writefd, buff , n); } else { while( (n = read(fd, buff, 4096)) > 0) { std::cout << "the server read file:" << buff; write(writefd, buff , n); } close(fd); }}void client(int readfd, int writefd){ size_t len; size_t n; char buff[4097]; std::cout<< "pls input filename" << std::endl; fgets(buff, 4096, stdin); len = strlen(buff); if( buff[len-1] == '/n') len--; write(writefd, buff, len); while( (n = read(readfd, buff ,4096)) > 0) { std::cout << "the client read message from server:" <<buff; }}

有一个test文件文件有一行数据this is a test 这里写图片描述