求c io高手解答

2012-06-04 11:52:05 184 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

C51单片机练习题目及解答（一） 1、掌握单片机的 IO 口输出：LED 实现不同的闪烁效果（快速闪烁，间隔 500ms 闪烁，亮灭各 1 秒），用示波器测试下 1s 的时间是否正确； #include<reg52.h> #include<intrins.h> #define uchar unsigned char #define uint unsigned int uchar aa=0xfe; uc... 阅读详情

今天回来遇到一问题，





//1.txt文件大小为1444byte

//windows :

#include <io.h>



//linux #include <unistd.h>



#include <fcntl.h>

/*#include <stdio.h>*/



int main(void)

{

//    FILE * file = fopen("f:/temp/1.txt", "rb");

    int fd = 0;

    char buff[1024];

    int reads = 0;

    int counts = 0;

//    fd = file->_file;

    fd = _open("f:/temp/1.txt", O_RDONLY, 0777);



    while ((reads = _read(fd, buff, sizeof(buff))) > 0) {

        counts += reads;

    }



    reads += 0;

    return 0;

}

//xp3下vs2008，counts 为1408, ubuntu 12.04下gcc，counts为1444



// #include <io.h>

// #include <fcntl.h>

#include <stdio.h>



int main(void)

{

    FILE * file = fopen("f:/temp/1.txt", "rb");

    int fd = 0;

    char buff[1024];

    int reads = 0;

    int counts = 0;

    fd = file->_file;

//    fd = _open("f:/temp/1.txt", O_RDONLY, 0777);



    while ((reads = _read(fd, buff, sizeof(buff))) > 0) {

        counts += reads;

    }



    reads += 0;

    return 0;

}

//xp3下vs2008，counts 为1444