/******************************************************************* * 這是一段用戶層的測試程序應(yīng)用代碼 *	$$$$  運(yùn)行在用戶空間 * 按下面的命令編譯: * usr/local/arm/2.95.3/bin/arm-linux-gcc -o drvtest drvtest.c *  *******************************************************************/#include <unistd.h>#include <stdio.h>#include <fcntl.h>#include "drv.h"int main(void){	int fd = -1;	int num;	int ret;		fd = open("/dev/cyc_io",O_RDWR);	if(fd<0){		printf("Can't open\n");		return -1;	}	else{		printf("Open OK %x\n", fd);	}	while(1)	{		printf("Enter a number:\n");		scanf("%d", &num);                		ret = ioctl(fd, IOCTL_SET_MSG, &num);				ret = write(fd, &num, 4);		num = 0;		//先清0,然后再看從內(nèi)核中讀出的一個(gè)數(shù)是否為寫入內(nèi)核的值		ret = read(fd, &num, 4);		printf("Read a number:%d\n",num);	}	close(fd);	return 0;}