p10.2.c

linux编程源代码,其中是由大量的实例

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

int main(int argc,char* argv[])
{
	int f_des1[2];
	int f_des2[2];

	int pid;
	char msg[BUFSIZ];
	char p_msg[BUFSIZ];
	
	if(argc!=2){
		printf("Usage: %s message\n",argv[0]);
		return 1;
	}

	if(pipe(f_des1)==-1){
		perror("cannot create the IPC pipe");
		return 1;
	}


	if(pipe(f_des2)==-1){
		perror("cannot create the IPC pipe");
		return 1;
	}

	pid=fork();
	if(pid==-1){
		perror("cannot create new process");
		return 1;
	}else if(pid==0){
		close(f_des1[1]);
		close(f_des2[0]);
		
		//read data from the parent process
		if(read(f_des1[0],msg,BUFSIZ)==-1){
			perror("child process cannot read data from pipe");
			return 1;
		}else
			printf("in child process, receive message: %s\n",msg);
		
		//write data to the parent process
                if(write(f_des2[1],msg,strlen(msg))==-1){
                        perror("child  process cannot write data to pipe");
                        return 1;
                }else
                        printf("in child  process, send message back: %s\n",argv[1]);

		_exit(0);
	}else {
		close(f_des1[0]);
		close(f_des2[1]);
		
		//write data to the child process	
		if(write(f_des1[1],argv[1],strlen(argv[1]))==-1){
			perror("parent process cannot write data to pipe");
			return 1;
		}else
			printf("in parent process, send message: %s\n",argv[1]);
		
		//read data from the cild process
                if(read(f_des2[0],p_msg,BUFSIZ)==-1){
                        perror("parent process cannot read data from pipe");
                        return 1;
                }else
                        printf("in parent process, receive message: %s\n",p_msg);

	       	
		wait(NULL);
		_exit(0);
	}

	return 0;
}