管道（PIPE）

代码：

#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/wait.h>
int main()
{
		int _pipe[2]; 
		int ret = pipe(_pipe); 
		if(ret == -1){ 
				printf("create pipe error! errno code is : %d\n",errno); 
				return 1;
		} 
		pid_t id = fork(); 
		if( id < 0 ){ 
				printf("fork error!"); 
				return 2; 
		}
		else if( id == 0 )
		{ //child 
				close(_pipe[0]); //close read
				int i =0; 
				char *_mesg_c=NULL; 
				while(i<10)
				{ 
					_mesg_c="i am child!"; 
					printf("write............%d\n", write(_pipe[1], _mesg_c, strlen(_mesg_c) + 1);)
					sleep(1); 
					i++; 
				} 
				close(_pipe[1]); //close write 
		}
		else
		{ //father 
				close(_pipe[1]); //close write 
				char _mesg[100]; 
				int j = 0;
			    sleep(3);	
				while(j<100)
				{ 
						memset(_mesg, '\0', sizeof(_mesg)); 
						int ret = read(_pipe[0], _mesg, 12); 
						if (ret < 0)
						{
							printf("pipe is read done...\n ");
							break;
						}
						printf("%s : code is : %d\n",_mesg, ret); 
						j++; 
				} 
				if (waitpid(id, NULL, 0)< 0) 
				{ 
						return 3; 
				} 
			} 
		return 0; 
}

运行结果：