Linux编程(清华大学出版社2019年1月第1版)第7章-进程间通信-课后作业

7.1

输出:

4:ABCD 
4:EFGH

输出:

numbers=3 
10 
20 
30

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <limits.h>
#include <fcntl.h>
#include <sys/types.h>
#include <stdint.h>
#include <string.h>

#define BUFSIZ 1024

struct grade 
{
	char sno[20];
	char name[10];
	float chinese,math,english;
};

int main()
{
	int fds[2];
	if (pipe(fds) < 0)
	{
		fprintf(STDERR_FILENO,"pipe failure \n");
		exit(EXIT_FAILURE);
	}
	int pid = fork();
	if (pid == 0) 
	{
		close(fds[0]);
		write(fds[1],"1234567890",11);
		struct grade gra = {"001","nihao",60,60,60};
		write(fds[1],&gra,sizeof(struct grade));
		close(fds[1]);
	}
	else 
	{
		close(fds[1]);
		uint8_t buff[BUFSIZ];
		read(fds[0],buff,sizeof(buff));
		printf("read num: %s \n",buff);
		struct grade *gra = buff+strlen(buff)+1;
		printf("read grade{name:%s, sno:%s, chi:%.2f, math:%.2f, eng:%.2f} \n"
			,gra->name,gra->sno,gra->chinese,gra->math,gra->english);
		close(fds[0]);
	}
	exit(EXIT_SUCCESS);
}

在这里插入图片描述

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>

int main() 
{
	printf("\n");
	int pipe_ids[2];
	pipe(pipe_ids);
	int pid0 = fork();
	if (pid0 == 0)
	{
		close(pipe_ids[0]);
		int save_stdout = dup(1); // save stdout
		close(1); // close stdout
		dup(pipe_ids[1]); // stdout -> pipe_ids[1]
		execlp("ps","ps","-aux",NULL);
		dup2(save_stdout,1); // restore stdout
		close(pipe_ids[1]);
		exit(EXIT_SUCCESS);
	}
	int pid1 = fork();
	if (pid1 == 0) 
	{
		close(pipe_ids[1]);
		int save_stdin = dup(0); // save stdin
		close(0); // close stdin
		dup(pipe_ids[0]); // stdin -> pipe_ids[0]
		execlp("grep","grep","init",NULL);
		dup2(save_stdin,0); // restore stdin
		close(pipe_ids[0]);
		exit(EXIT_SUCCESS);
	}
	close(pipe_ids[0]);
	close(pipe_ids[1]);
	return 0;
}