1.首先要打开目录文件

DIR *opendir( const char *name);

DIR *fdopendir( int fd);

2.读取目录文件信息的函数    

注意：这是个库函数

struct dirent *readdir( DIR *dirp);

int readdir_r(    DIR *dirp,     struct dirent *entry,    struct dirent **result);

文件目录结构体：

struct dirent {ino_t          d_ino;       /* inode number 索引节点号*/off_t          d_off;       /* not an offset; see NOTES 在目录文件中的偏移*/unsigned short d_reclen;    /* length of this record 文件名长*/unsigned char  d_type;   /*type of file; not supported by all  filesystem types 文件类型*/              char           d_name[256]; /* filename 文件名，最长255字符*/
};

d_type的值为：

• DT_BLK This is a block device.
• DT_CHR This is a character device.
• DT_DIR This is a directory.
• DT_FIFO This is a named pipe (FIFO).
• DT_LNK This is a symbolic link.
• DT_REG This is a regular file.
• DT_SOCK This is a UNIX domain socket.
• DT_UNKNOWN The file type is unknown.

readdir（）函数实例：

注意：

每次使用readdir后，readdir会读到下一个文件，readdir是依次读出目录中的所有文件，每次只能读一个

这个特性和readdir_r()一样

#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
int main(int argc, char **argv){DIR *pDir = NULL;struct dirent * pEnt = NULL;unsigned int cnt = 0;	if (argc != 2){printf("usage: %s dirname\n", argv[0]);return -1;}pDir = opendir(argv[1]);if (NULL == pDir){perror("opendir");return -1;}	while (1){pEnt = readdir(pDir);if(pEnt != NULL){if (pEnt->d_type == DT_REG){printf("是普通文件:");}else{printf("不是普通文件:");}printf("name：[%s]	\n", pEnt->d_name);cnt++;}else{break;}};printf("总文件数为：%d\n", cnt);return 0;
}

结果：

$ ./a.out .
是普通文件:name：[a.c]	
不是普通文件:name：[.]	
不是普通文件:name：[..]	
是普通文件:name：[a.out]	
不是普通文件:name：[12_sr]	
不是普通文件:name：[10_sr]	
不是普通文件:name：[17_sr]	
不是普通文件:name：[15_sr]	
不是普通文件:name：[14.sr]	
不是普通文件:name：[18_sr]	
不是普通文件:name：[udp]	
不是普通文件:name：[16_sr]	
不是普通文件:name：[tcp]	
总文件数为：13

C++

#include <iostream>
#include <string>
using namespace std;
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <dirent.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <dirent.h>void search(string commonXmlPath){
{string ectPath = commonXmlPath;string subDistrictXmlPath;DIR* dir_pointer = opendir(ectPath.c_str());if (!dir_pointer)return;for (dirent* dp = readdir(dir_pointer); dp != NULL; dp = readdir(dir_pointer)){std::string filename = dp->d_name;if (filename == "." || filename == ".."){continue;}if (dp->d_type == 8)//?录镁{int split = filename.find('.');if (split == -1)continue;string pp =  ectPath + filename;cout << pp.c_str() <<"\n";}if(dp->d_type == 4)//目录拢卢?么录?酶碌梅                        {//每赂枚募镁录?路戮露subDistrictXmlPath = ectPath + string("/") + dp->d_name;search(subDistrictXmlPath);}}//closedir(dir_pointer);
}
int main(){search(string("/data/home/android/configserver/common_xmls/etc"));return 0;
}

readdir_r():

注意：

这三个参数

#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <stdlib.h>
int main(int argc, char **argv)
{DIR *pDir = NULL;struct dirent * pEnt = NULL;struct dirent *entry = (struct dirent *)malloc(sizeof(struct dirent));struct dirent **result = (struct dirent **)malloc(sizeof(struct dirent));unsigned int cnt = 0;unsigned int ret = 0;	if (argc != 2){printf("usage: %s dirname\n", argv[0]);return -1;}pDir = opendir(argv[1]);if (NULL == pDir){perror("opendir");return -1;}ret = readdir_r(pDir , entry , result);printf("return	:%d	\n", ret);printf("name	:[%s]	\n", entry->d_name);printf("name	:[%s]	\n", result[0]->d_name);ret = readdir_r(pDir , entry , result);printf("return	:%d	\n", ret);printf("name	:[%s]	\n", entry->d_name);printf("name	:[%s]	\n", result[0]->d_name);return 0;}

结果：