LINUX下用C語言歷遍目錄 C語言列出目錄2007-04-06 21:02功能：       Linux下C語言目錄歷遍 (讀取目錄)

作者：       小徐

QQ:          339534039

轉載請注明出處

呵呵，LINUX下歷遍目錄的方法一般是這樣的

打開目錄-》讀取-》關閉目錄

相關函數是

opendir -> readdir -> closedir

#include <dirent.h>

DIR *opendir(const char *dirname);

#include <dirent.h>

struct dirent *readdir(DIR *dirp);

#include <dirent.h>

int closedir(DIR *dirp);

好了，三個函數都出來了呵呵，原型就是上面，給自己解釋一下免得以后我自己忘了呵呵！我以經忘過好幾回了，所以這次放上博客來

opendir用于打開目錄，是類似于流的那種方式，返回一個指向DIR結構體的指針他的參數*dirname是一個字符數組或者字符串常量,

readdir函數用于讀取目錄，他只有一個參數，這個參數主opendir返回的結構體指針，或者叫句柄更容易理解些吧。這個函數也返回一個結構 體指針 dirent *

dirent的結構如下定義

    struct dirent

    {

        long d_ino;                      /* inode number */

        off_t d_off;                     /* offset to this dirent */

        unsigned short d_reclen;         /* length of this d_name */

        char d_name [NAME_MAX+1];        /* file name (null-terminated) */

    }

結構體中d_ino存放的是該文件的結點數目，什么是結點數目呢我也說不清楚了呵呵，查一下其它資料了

d_off 是文件在目錄中的編移，具體是什么意思我也不是很明白，我很少用到它，其本上就是用到d_name short d_reclen是這個文件的長度，需要注意的是這里的長度并不是指文件大小，因為大小和長度是2回事了，你可以用lseek將文件長度移得很長，但大小 其實還是那么大.最后一個元素就是我們要的了，文件名稱！

寫了一個實例:

/**

* 功能：       Linux下C語言目錄歷遍 (讀取目錄)

* 作者：       小徐

* 郵箱：      xjtdy888@163.com

* QQ:          339534039

* 轉載請注明出處

*/

#include <stdio.h>

#include <stdlib.h>

#include <sys/types.h>

#include <unistd.h>

#include <dirent.h>

void print_usage(void);

void print_usage(void)

{

printf("Usage: test dirname\n");

}

int main(int argc,char *argv[])

{

DIR * dp;

struct dirent *filename;

if (argc < 2)

{

       print_usage();

       exit(1);

}

dp = opendir(argv[1]);

if (!dp)

{

       fprintf(stderr,"open directory error\n");

       return 0;

}

while (filename=readdir(dp))

{

       printf("filename:%-10s\td_info:%ld\t d_reclen:%us\n",

         filename->d_name,filename->d_ino,filename->d_reclen);

}

closedir(dp);

return 0;

}

將上面代碼保存為readdir.c執行下面的命令進行編譯測試

[root@phpos ~]# gcc readdir.c

[root@phpos ~]# ./a.out

Usage: test dirname

[root@phpos ~]# ./a.out /etc/samba/

filename:lmhosts             d_info:49296          d_reclen:24s

filename:smb.conf            d_info:49825          d_reclen:24s

filename:smbpasswd           d_info:49402          d_reclen:24s

filename:..                  d_info:47906          d_reclen:16s

filename:secrets.tdb         d_info:49812          d_reclen:24s

filename:.                   d_info:49295          d_reclen:16s

filename:smbusers            d_info:49377          d_reclen:24s

[root@phpos ~]# ./a.out /var/

filename:preserve            d_info:31971          d_reclen:24s

filename:lock                d_info:31966          d_reclen:16s

filename:yp                  d_info:31976          d_reclen:16s

filename:empty               d_info:31962          d_reclen:24s

filename:run                 d_info:31972          d_reclen:16s

filename:lib                 d_info:31939          d_reclen:16s

filename:nis                 d_info:31969          d_reclen:16s

filename:local               d_info:31965          d_reclen:24s

filename:spool               d_info:31973          d_reclen:24s

filename:tmp                 d_info:31941          d_reclen:16s

filename:opt                 d_info:31970          d_reclen:16s

filename:log                 d_info:31959          d_reclen:16s

filename:crash               d_info:31997          d_reclen:24s

filename:..                  d_info:2              d_reclen:16s

filename:account             d_info:32037          d_reclen:24s

filename:mail                d_info:31968          d_reclen:16s

filename:cache               d_info:31960          d_reclen:24s

filename:db                  d_info:31961          d_reclen:16s

filename:.                   d_info:31938          d_reclen:16s

[root@phpos ~]#

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