pipe_cmd.c

关于进程间通信的代码集锦2

#include <unistd.h>
#include <sys/types.h>
#include <errno.h>

int main()
{
	int pipe_fd[2];
	pid_t pid;
	char r_buf[4];
	char** w_buf[256];	
	int childexit=0;
	int cmd;
	int i;	
	memset(r_buf,0,sizeof(r_buf));
	if(pipe(pipe_fd)<0)
	{
		printf("pipe create error\n");
		return -1;
	}

	if((pid=fork())==0)
	{
		printf("In child process\n");		
		close(pipe_fd[1]);
		while(!childexit)
		{	
			read(pipe_fd[0],r_buf,4);
			cmd=atoi(r_buf);
			if(cmd==0)	
			{	
				printf("child:receive command from parent over\n now child process exit\n");
				childexit=1;
			}
			else if(handle_cmd(cmd)!=0)
			{
				return;
			}
			sleep(1);
		}
		printf("sdfsdfsd");
		close(pipe_fd[0]);
		exit(0);
	}
	else if(pid>0)
	{		
		printf("In parent process\n");
		close(pipe_fd[0]);
		w_buf[0]="003";
		w_buf[1]="005";
		w_buf[2]="777";
		w_buf[3]="000";
		
		for(i=0;i<4;i++)
		{
			write(pipe_fd[1],w_buf[i],4);
		}
		sleep(5);
		close(pipe_fd[1]);
	}
	return 0;
}
int handle_cmd(int cmd)
{
	if((cmd<0)||(cmd>256))
	{
		printf("child:invalid command\n");
		return -1;
	}
	printf("child:the cmd from parent is %d\n",cmd);
	return 0;
}