file.txt

实验演示了在uClinux中实现文件的打开和读写操作

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

#define TEST_STRING "TEST file operation on different FS"

int main(int argc,char * argv[])
{
	int fd,op_flag;
	char * filename;
	int len;
	char buf[128];
	
	/* check input parameters */
	if(argc < 2)
	{
		fprintf(stderr,"please give filename");
		exit(1);			
	}
	
	/* open file */
	filename = argv[1];
	op_flag = O_RDWR | O_CREAT;
	
	if((fd=open(filename,op_flag)) <0)
	{/* open error */
		fprintf(stderr,"open file %s error",filename);
		exit(1);			
	}
	
	/* write file  */
	if((len = write(fd,TEST_STRING,strlen(TEST_STRING)+1)) != strlen(TEST_STRING)+1)
	{/* write file error */
		fprintf(stderr,"write file %s error",filename);
		exit(1);			
	}
	/* seek current file pointer to the start of file */
	if(lseek(fd,0,SEEK_SET) !=  0)
	{
		fprintf(stderr,"fseek file %s error",filename);
		exit(1);
	}
	
	/* read file */
	if((len = read(fd,buf,128)) != strlen(TEST_STRING)+1)
	{/* read file error */
		fprintf(stderr,"read file %s len error",filename);
		exit(1);		
	}
	
	/* compare write-read */
	if(memcmp(TEST_STRING,buf,len) != 0)
	{/* content different */
		fprintf(stderr,"check file %s content error",filename);
		exit(1);			
	}
	
	printf("\nfile %s open-write-read ok \n",filename);	
	
	/* close fd */
	close(fd);	
	
	return 0;
}