一 测试程序头文件 scull.h

#include <linux/ioctl.h> /* needed for the _IOW etc stuff used later */
/*
 * Ioctl definitions
 */

/* Use 'k' as magic number */
#define SCULL_IOC_MAGIC  'k'
/* Please use a different 8-bit number in your code */

#define SCULL_P_IOCTSIZE _IO(SCULL_IOC_MAGIC,   0)
#define SCULL_P_IOCQSIZE _IO(SCULL_IOC_MAGIC,   1)

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <stropts.h>
#include <linux/poll.h>
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include "scull.h"

int main()
{
	char buffer1[20]={0};
	int pipetest0, pipetest1;
	int code=21, i=0;
       struct pollfd poll_list[2];
       int retval;


	
	if ((pipetest0 = open("/dev/scullpipe0",O_RDONLY)) < 0)	{
		 printf("open scullpipe0 error! \n"); 
		exit(1);
	}
	 printf("open scullpipe0 ! \n"); 

	if ((pipetest1 = open("/dev/scullpipe1",O_RDONLY)) < 0)	{
		 printf("open scullpipe1 error! \n"); 
		exit(1);
	}
	 printf("open scullpipe1 ! \n"); 

	if ( ioctl(pipetest0 ,  SCULL_P_IOCTSIZE , code ) < 0) 	{
		 printf("pipetest0 ioctl  SCULL_P_IOCTSIZE error! \n"); 
		exit(1);
	}

	printf(" SCULL_P_IOCTSIZE : scull_p_buffer0=%d !\n" ,ioctl( pipetest0 , SCULL_P_IOCQSIZE , NULL ) );


	if ( ioctl(pipetest1 ,  SCULL_P_IOCTSIZE , code ) < 0) 	{
		 printf("pipetest1 ioctl  SCULL_P_IOCTSIZE error! \n"); 
		exit(1);
	}

	printf(" SCULL_P_IOCTSIZE : scull_p_buffer1=%d !\n" ,ioctl( pipetest1 , SCULL_P_IOCQSIZE , NULL ) );

	close(pipetest0);
	printf("close pipetest0 ! \n"); 
	close(pipetest1);
	printf("close pipetest1 ! \n"); 
	if ((pipetest0 = open("/dev/scullpipe0",O_RDONLY)) < 0)	{
		 printf("reopen scullpipe0 error! \n"); 
		exit(1);
	}
	 printf("reopen scullpipe0 ! \n"); 

	if ((pipetest1 = open("/dev/scullpipe1",O_RDONLY)) < 0)	{
		 printf("reopen scullpipe1 error! \n"); 
		exit(1);
	}
	 printf("reopen scullpipe1 ! \n"); 


       poll_list[0].fd = pipetest0;
       poll_list[1].fd = pipetest1;
       poll_list[0].events = POLLIN|POLLRDNORM;
       poll_list[1].events = POLLIN|POLLRDNORM;
  
       while(1)
       {
           retval = poll(poll_list,(unsigned long)2,-1);
           /* retval 鎬绘槸澶т簬0鎴栦负-1锛屽洜涓烘垜浠湪闃诲涓伐浣?*/
  
           if(retval < 0)
		{
               fprintf(stderr,"poll閿欒: %s\n",strerror(errno));
               return -1;
		}
    
           if(poll_list[0].revents&(POLLIN|POLLRDNORM)) 
		{
				if ((code=read(pipetest0 , buffer1 , 20)) != 20) printf("read from pipetest0 error! code=%d\n",code);
				else   printf("read from pipetest0 ok! code=%d \n",code);
				
				for(i=0;i<20;i+=5) 
					printf("[%d]=%c [%d]=%c [%d]=%c [%d]=%c [%d]=%c\n",i,buffer1[i],i+1,buffer1[i+1],i+2,buffer1[i+2],i+3,buffer1[i+3],i+4,buffer1[i+4]);
			
		}

           if(poll_list[1].revents&(POLLIN|POLLRDNORM)) 
		{
				if ((code=read(pipetest1 , buffer1 , 20)) != 20) printf("read from pipetest1 error! code=%d \n",code);
				else   printf("read from pipetest1 ok! code=%d \n",code);
				
				for(i=0;i<20;i+=5) 
					printf("[%d]=%c [%d]=%c [%d]=%c [%d]=%c [%d]=%c\n",i,buffer1[i],i+1,buffer1[i+1],i+2,buffer1[i+2],i+3,buffer1[i+3],i+4,buffer1[i+4]);

		}

       }

	close(pipetest0 );
	printf("close pipetest0  ! \n"); 
	close(pipetest1 );
	printf("close pipetest1 ! \n"); 

	printf("\n"); 
  exit(0);

}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#inclu