IO线程进程（5月11）（进程间通讯）

1、

#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <sys/wait.h>
int main(int argc, const char *argv[])
{
		umask(0);
	if(mkfifo("./fifo1",0777)<0){
		if(errno!=17){
			perror("mkfifo");
			return -1;
		}
	}
	printf("create FIFO1 success\n");
	if(mkfifo("./fifo2",0777)<0){
		if(errno!=17){
			perror("mkfifo");
			return -1;
		}
	}
	printf("create FIFO2 success\n");

	//int fd= open("./fifo",O_RDONLY|O_NONBLOCK);
	//int fd= open("./fifo",O_WRONLY|O_NONBLOCK);
	pid_t pid=fork();
	if(pid>0){
		int fd= open("./fifo1",O_RDWR);
		if(fd<0){
			perror("open");
			return -1;
		}
		printf("open success\n");
	int fd2= open("./fifo2",O_RDWR);
		if(fd2<0){
			perror("open");
			return -1;
		}
		printf("open success\n");

		char buf[128]="";
		ssize_t res;

		while(1){
			printf("父进程请输入：\n");
			fgets(buf,sizeof(buf),stdin);
			buf[strlen(buf)-1]=0;
			if(write(fd,buf,sizeof(buf))<0){
				perror("write");
				return -1;
			}
			printf("write success\n");
			if(!strcmp(buf,"quit")){
				break;
			}
			bzero(buf,sizeof(buf));
			res=read(fd2,buf,sizeof(buf));
			if(res<0){
				perror("read");
				return -1;
			}
			else if(0==res){
				printf("写入端全部关闭，且管道中没有数据\n");
				break;
			}
			printf("res=%ld  buf=%s\n",res,buf);
			if(!strcmp(buf,"quit")){
				break;
			}



		}
		close(fd);
		close(fd2);
		wait(NULL);

	}
	else if(0==pid){
		char buf[128]="";
		int fd= open("./fifo1",O_RDWR);
		if(fd<0){
			perror("open");
			return -1;
		}
	int fd2= open("./fifo2",O_RDWR);
		if(fd2<0){
			perror("open");
			return -1;
		}

		ssize_t res;
		while(1){
			bzero(buf,sizeof(buf));
			res=read(fd,buf,sizeof(buf));
			if(!strcmp(buf,"quit")){
				break;
			}

			if(res<0){
				perror("read");
				return -1;
			}
			else if(0==res){
				printf("写入端全部关闭，且管道中没有数据\n");
				break;
			}
			printf("res=%ld  buf=%s\n",res,buf);
			printf("子进程请输入：\n");
			bzero(buf,sizeof(buf));

			fgets(buf,sizeof(buf),stdin);
			buf[strlen(buf)-1]=0;
			if(write(fd2,buf,sizeof(buf))<0){
				perror("write");
				return -1;
			}
			printf("write success\n");
			if(!strcmp(buf,"quit")){
				break;
			}
		

		}
		close(fd);
		close(fd2);
	}
	else if(pid<0){
		perror("fork");
		return -1;
	}





	
	return 0;
}

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