测试用指定块大小读取文件时间的代码

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include <sys/types.h>
#include <sys/xattr.h>
#include <sys/stat.h>
#include <pthread.h>
#include <fcntl.h>
#include <utime.h>
#include <sys/time.h>
#include <errno.h>
#include <dirent.h>
#include<sys/time.h>

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include <sys/types.h>
#include <sys/xattr.h>
#include <sys/stat.h>
#include <pthread.h>
#include <fcntl.h>
#include <utime.h>
#include <sys/time.h>
#include <errno.h>
#include <dirent.h>
#include<sys/time.h>

int main(int argv,char*argc[])
{
        int i=512;//指定读取的块的大小
        int j=i*1024;
        char databuf[j];

 struct timeval t_start,t_end;
 long const_timeopen=0;
 long const_timeread=0;

 //get opent sart time
 gettimeofday(&t_start,NULL);
 printf("start open time :%ld us\n",t_start.tv_usec);

         int file=open(argc[1],O_RDONLY);//输入要去的文件名
 if (file == -1) {
                close (file);
             printf("error\n");}

        while(0<read(file,databuf,32*1024)){

//      printf("databuf=%s\n",databuf);
        }

        close(file);

 //get end time
 gettimeofday(&t_end,NULL);
 printf("end open time:%ld us\n",t_end.tv_usec);

 //const open time
 const_timeopen=t_end.tv_usec-t_start.tv_usec;
 printf("const open time :%ld us\n",const_timeopen);

printf("over!\n");

}