testdrv.c

一个linux下字符设备驱动程序的编写例子

#include<stdio.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
 
int  main()
{	
	int testdev;
	int i;
	char buf[100];
	char buf1[100]="The content you just written in it!!!";
	char buf2[200];
	if((testdev=open("/dev/mychardrv",O_RDWR))==-1)
	{	
		printf("！！！打开该设备文件操作失败！！！\n");
		exit(0);
	}
	printf("\n###******************Function Read Test**********************###\n");
	read(testdev,buf2,200);
	printf("######Content  Of   The  Device######\n");
	printf("%s\n",buf2);
	printf("######Content  Just  Read#####\n");
	lseek(testdev,164,0);
	read(testdev,buf,40);
	printf("%s\n",buf);
	printf("\n###******************Function Write Test**********************###\n");
	lseek(testdev,41,0);
   	write(testdev,buf1,40);
	lseek(testdev,41,0);
	read(testdev,buf,40);
	printf("%s\n",buf);
	close(testdev);
	return  0;
}