demo.c

来自「一个Linux系统字符驱动的源代码」· C语言 代码 · 共 47 行

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>


int main()
{
	int fd,i,nwrite,nread;
	char *buf="HELLO WORLD!";
	char read_buf[1024]={0}; // user space buffer
	fd=open("/dev/szx",O_RDWR);
	if(fd<=0)
	{
		perror("ERROR in opening this file, please CHECK the device!");
		exit(1);
	}
	else
		printf("File open SUCCESSFUL!\n");
    
    
    nwrite=write(fd,buf,strlen(buf)); // write data to myfs
	
	if(nwrite<0)
	{
		perror("ERROR in writing this file!");
		exit(1);
	}
    printf("PRESS ANY KEY TO CONTINUE...");
	getchar();

	nread=read(fd,read_buf,1024);  //read data from myfs
	if(nread<0)
	{
		perror("ERROR in reading this file!");
		exit(1);
	}
	else
		printf("The written string is:  %s\n",read_buf);
	
	close(fd);
	exit(0);
}