目录操作

文件IO下目录操作

1、打开目录opendir()

#include <sys/types.h>
include <dirent.h>
DIR *opendir(const char *name);

返回值：成功返回目录流指针，失败返回NULL；
参数：name：目录名

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <dirent.h>
int main(int argc, char *argv[])
{
	
	DIR *dir = opendir(".");//打开当前目录
	if(dir == NULL)
	{
		perror("opendir");
		return -1;
	}

	printf("success!\n");

	return 0;
}

2、读取目录 redadir()

#include <dirent.h>
struct dirent *readdir(DIR *dirp); 

返回值：成功返回对应目录项结构体指针，失败返回NULL；

3.关闭目录

#include <sys/types.h>
#include <dirent.h>
int closedir(DIR *dirp);

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <dirent.h>
int main(int argc, char *argv[])
{
	struct dirent *fl;


	DIR *dir = opendir(".");
	if(dir == NULL)
	{
		perror("opendir");
		return -1;
	}

	
	while((fl = readdir(dir)) != NULL)
	{
		if(fl->d_name[0] != '.')
		{
			printf("%s  ", fl->d_name);
		}
	}
	printf("\n");
	closedir(dir);
	return 0;
}

4.获取文件属性

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

int stat(const char *path, struct stat *buf);

int lstat(const char *path, struct stat *buf);
	   
int fstat(int fd, struct stat *buf);

返回值：成功返回0，失败返回-1；

参数：
path：文件名(包含路径)

S_IFMT 0170000 文件类型掩码

st_mode & S_IFMT == S_IFREG --> 普通文件

							   **== S_IFDIR   --> 目录文件**

				S_IFSOCK   0140000   socket
				S_IFLNK    0120000   symbolic link
				S_IFREG    0100000   regular file
				S_IFBLK    0060000   block device
				S_IFDIR    0040000   directory
				S_IFCHR    0020000   character device
				S_IFIFO    0010000   FIFO				

st_mode & 对应权限宏 == 宏本身 则拥有对应权限

		   S_IRUSR    00400     owner has read permission
           S_IWUSR    00200     owner has write permission
           S_IXUSR    00100     owner has execute permission

		   S_IRGRP    00040     group has read permissio
           S_IWGRP    00020     group has write permission
           S_IXGRP    00010     group has execute permission

		   S_IROTH    00004     others have read permission
           S_IWOTH    00002     others have write permission
           S_IXOTH    00001     others have execute permission

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/stat.h>
#include <unistd.h>

int main(int argc, char *argv[])
{
	struct dirent *fl;
	struct stat buf;
	int ret = 0;

	DIR *dir = opendir(".");
	if(dir == NULL)
	{
		perror("opendir");
		return -1;
	}

	
	while((fl = readdir(dir)) != NULL)  //读取目录项
	{
		if(fl->d_name[0] != '.')
		{
			ret = lstat(fl->d_name, &buf);    //获取文件属性
			if(ret < 0)
			{
				perror("lstat");
				return -1;
			}

			localtime(&buf.st_ctime);
	
			switch(buf.st_mode & S_IFMT)
			{
				case S_IFREG:
					printf("-");  break;
				case S_IFDIR:
					printf("d");  break;
			}

			printf("  %d %d %s\n",buf.st_nlink ,buf.st_size, fl->d_name);


		}
	}
	printf("\n");
	closedir(dir);
	return 0;
}