A进程

#include <head.h>
int main(int argc, const char *argv[])
{
	pid_t cpid=fork();

	if(cpid>0)//父进程向管道文件2写
	{	int wfd;
		if((wfd=open("./myfifo2",O_WRONLY))==-1)
		{
			ERR_MSG("open");
			return -1;

		}	
		char buf[128]="";
		while(1)
		{
			bzero(buf,sizeof(buf));
			putchar(10);
			printf("B进程请输入:");
			fgets(buf,sizeof(buf),stdin);
			buf[strlen(buf)-1]=0;
			write(wfd,buf,sizeof(buf));
			if(strcmp(buf,"q")==0)
			{
				printf("写进程退出\n");
				break;
			}


		}
		close(wfd);
	}
	else if(0==cpid)//子进程从管道文件1读取
	{
		
		int rfd;
		char buf1[128]="";
		if((rfd=open("./myfifo1",O_RDONLY))==-1)
		{
			ERR_MSG("open");
			return -1;

		}


		while(1)
		{
			bzero(buf1,sizeof(buf1));
			read(rfd,buf1,sizeof(buf1));
			if(strcmp(buf1,"q")==0)
			{
				printf("写进程退出\n");
				break;
			}
			putchar(10);
			printf("A进程向B进程输出数据为%s\n",buf1);

		}
		close(rfd);
	
	}
	else 
	{
		ERR_MSG("fork");
		return -1;
	}

 	return 0;
}        

 

 B进程

#include <head.h>
int main(int argc, const char *argv[])
{
	pid_t cpid=fork();

	if(cpid>0)//父进程向管道文件1写
	{	int wfd;
		if((wfd=open("./myfifo1",O_WRONLY))==-1)
		{
			ERR_MSG("open");
			return -1;

		}	
	char buf[128]="";
		while(1)
		{
			bzero(buf,sizeof(buf));
			putchar(10);
			printf("A进程请输入");
			fgets(buf,sizeof(buf),stdin);
			buf[strlen(buf)-1]=0;
			write(wfd,buf,sizeof(buf));
			if(strcmp(buf,"q")==0)
			{
				printf("写进程退出\n");
				break;
			}


		}
		close(wfd);
	}
	else if(0==cpid)//子进程从管道文件2读取
	{
		
		int rfd;
		char buf1[128]="";
		if((rfd=open("./myfifo2",O_RDONLY))==-1)
		{
			ERR_MSG("open");
			return -1;

		}


		while(1)
		{	int wfd;
	if((wfd=open("./myfifo1",O_WRONLY))==-1)
	{
		ERR_MSG("open");
		return -1;

	}	
	char buf[128]="";
			bzero(buf1,sizeof(buf1));
			read(rfd,buf1,sizeof(buf1));
			if(strcmp(buf1,"q")==0)
			{
				printf("写进程退出\n");
				break;
			}
			putchar(10);
			printf("B进程向A进程输出数据为%s\n",buf1);

		}
		close(rfd);
	
	}
	else 
	{
		ERR_MSG("fork");
		return -1;
	}

 	return 0;
}