linux opendir和readdir的使用
1 opendir
#include
#include
DIR *opendir(const char *name);
传入name路径，成功则返回非空DIR指针，否则返回NULL
2 readdir
#include
struct dirent *readdir(DIR *dirp);
int readdir_r(DIR *dirp, struct dirent *entry, struct dirent **result);
readdir一般要配合opendir使用，readdir不是线程安全函数，代替他的有readdir_r。
readdir返回 struct dirent *指针，读完目录下所有文件时，返回NULL
如果系统支持readdir_r，建议用readdir_r , readdir_r成功返回0。
关于struct dirent结构体：
On Linux, the dirent structure is defined as follows:
struct dirent {
ino_t d_ino; /* inode number */
off_t d_off; /* not an offset; see NOTES */
unsigned short d_reclen; /* length of this record */
unsigned char d_type; /* type of file; not supported
by all filesystem types */
char d_name[256]; /* filename */
};
3 closedir
#include
#include
int closedir(DIR *dirp);
closedir配合opendir使用。
#include
#include
#include
#include
#include
#include
//DIR *opendir(const char *name);
#ifndef LOG_TRACE
#define LOG_TRACE printf
#define LOG_INFO(msg) \
do{ \
LOG_TRACE msg; \
LOG_TRACE("[%s %d] \n",__FUNCTION__,__LINE__);\
}while(0)
#define LOG_ERROR(err_info) \
do{ \
LOG_TRACE err_info; \
LOG_TRACE("[%s %d] \n",__FUNCTION__,__LINE__);\
}while(0)
#endif
extern int errno;
int open_dir_1(const char *pDirname)
{
DIR * dirp = NULL;
struct dirent * pDirent= NULL;
if((NULL == pDirname) ||
(0 == strlen(pDirname)))
{
LOG_ERROR(("param error"));
return -1;
}
dirp = opendir(pDirname);
if (NULL == dirp)
{
LOG_ERROR(("opendir %s failed! error_no: %s",pDirname , strerror(errno)));
return -1;
}
while (NULL != (pDirent = readdir(dirp)))
{
if (pDirent->d_type == DT_DIR )
{
LOG_ERROR(("dir [%s] ",pDirent->d_name));
}
else if(pDirent->d_type == DT_REG)
{
LOG_ERROR(("file [%s] ",pDirent->d_name));
}
}
closedir(dirp);
return 0;
}
int open_dir_2(const char *pDirname)
{
DIR * dirp = NULL;
struct dirent * pDirent= NULL;
struct dirent *pStResult = NULL;
if((NULL == pDirname) ||
(0 == strlen(pDirname)))
{
LOG_ERROR(("param error"));
return -1;
}
dirp = opendir(pDirname);
if (NULL == dirp)
{
LOG_ERROR(("opendir %s failed! error_no: %s",pDirname , strerror(errno)));
return -1;
}
pDirent = (struct dirent *)malloc(sizeof(struct dirent));
if(!pDirent)
{
LOG_ERROR(("pDirent error"));
closedir(dirp);
return -1;
}
while (( 0== readdir_r(dirp,pDirent,&pStResult))&&
(pStResult != NULL))
{
if (pDirent->d_type == DT_DIR )
{
LOG_ERROR(("dir [%s] ",pDirent->d_name));
}
else if(pDirent->d_type == DT_REG)
{
LOG_ERROR(("file [%s] ",pDirent->d_name));
}
}
closedir(dirp);
return 0;
}
int main()
{
LOG_ERROR(("***********"));
open_dir_1("/share/");
LOG_ERROR(("------------"));
open_dir_2("/share/");
LOG_ERROR(("-++--+++--"));
return 0;
}
运行结果：
./a.out [19@gcc test_opendir_readdir.c[C
root@ubuntu:/share#
root@ubuntu:/share#
root@ubuntu:/share# gcc test_opendir_readdir.c
/a.out
***********[main 113]
file [zlib-1.2.8.tar.gz] [open_dir_1 54]
file [1.tmp] [open_dir_1 54]
file [log.c] [open_dir_1 54]
file [list.c] [open_dir_1 54]
dir [11] [open_dir_1 50]
file [test.out] [open_dir_1 54]
file [test_system_func.c] [open_dir_1 54]
file [a.out] [open_dir_1 54]
file [test_strncpy.c] [open_dir_1 54]
file [test_proc_partitions.c] [open_dir_1 54]
file [test.c] [open_dir_1 54]
file [New0001.c] [open_dir_1 54]
dir [curl-7.51.0] [open_dir_1 50]
file [test_ftok.c] [open_dir_1 54]
file [log.h] [open_dir_1 54]
file [test_gettimeofday.c] [open_dir_1 54]
file [csdn.c] [open_dir_1 54]
file [client.c] [open_dir_1 54]
file [1.txt] [open_dir_1 54]
file [test_opendir_readdir.c] [open_dir_1 54]
file [curl-7.51.0.tar.gz] [open_dir_1 54]
file [2.txt] [open_dir_1 54]
file [opendir.c] [open_dir_1 54]
dir [zlib-1.2.8] [open_dir_1 50]
file [123.rmvb] [open_dir_1 54]
dir [ffmpeg_learn] [open_dir_1 50]
file [test_sem.c] [open_dir_1 54]
file [test_list.c] [open_dir_1 54]
file [list.h] [open_dir_1 54]
file [server] [open_dir_1 54]
dir [ProFFmpeg] [open_dir_1 50]
dir [ffmpeg-3.1.6] [open_dir_1 50]
dir [yasm-1.3.0] [open_dir_1 50]
file [New0003.c] [open_dir_1 54]
dir [.] [open_dir_1 50]
dir [..] [open_dir_1 50]
file [ffmpeg-3.1.6.tar.gz] [open_dir_1 54]
file [types.h] [open_dir_1 54]
file [New0002.c] [open_dir_1 54]
file [simple.out] [open_dir_1 54]
file [server.c] [open_dir_1 54]
dir [learn] [open_dir_1 50]
file [simple_ffmpeg_player.c] [open_dir_1 54]
file [client] [open_dir_1 54]
dir [abc] [open_dir_1 50]
file [yasm-1.3.0.tar.gz] [open_dir_1 54]
file [output.yuv] [open_dir_1 54]
file [mySDLFirst.out] [open_dir_1 54]
------------[main 115]
file [zlib-1.2.8.tar.gz] [open_dir_2 100]
file [1.tmp] [open_dir_2 100]
file [log.c] [open_dir_2 100]
file [list.c] [open_dir_2 100]
dir [11] [open_dir_2 96]
file [test.out] [open_dir_2 100]
file [test_system_func.c] [open_dir_2 100]
file [a.out] [open_dir_2 100]
file [test_strncpy.c] [open_dir_2 100]
file [test_proc_partitions.c] [open_dir_2 100]
file [test.c] [open_dir_2 100]
file [New0001.c] [open_dir_2 100]
dir [curl-7.51.0] [open_dir_2 96]
file [test_ftok.c] [open_dir_2 100]
file [log.h] [open_dir_2 100]
file [test_gettimeofday.c] [open_dir_2 100]
file [csdn.c] [open_dir_2 100]
file [client.c] [open_dir_2 100]
file [1.txt] [open_dir_2 100]
file [test_opendir_readdir.c] [open_dir_2 100]
file [curl-7.51.0.tar.gz] [open_dir_2 100]
file [2.txt] [open_dir_2 100]
file [opendir.c] [open_dir_2 100]
dir [zlib-1.2.8] [open_dir_2 96]
file [123.rmvb] [open_dir_2 100]
dir [ffmpeg_learn] [open_dir_2 96]
file [test_sem.c] [open_dir_2 100]
file [test_list.c] [open_dir_2 100]
file [list.h] [open_dir_2 100]
file [server] [open_dir_2 100]
dir [ProFFmpeg] [open_dir_2 96]
dir [ffmpeg-3.1.6] [open_dir_2 96]
dir [yasm-1.3.0] [open_dir_2 96]
file [New0003.c] [open_dir_2 100]
dir [.] [open_dir_2 96]
dir [..] [open_dir_2 96]
file [ffmpeg-3.1.6.tar.gz] [open_dir_2 100]
file [types.h] [open_dir_2 100]
file [New0002.c] [open_dir_2 100]
file [simple.out] [open_dir_2 100]
file [server.c] [open_dir_2 100]
dir [learn] [open_dir_2 96]
file [simple_ffmpeg_player.c] [open_dir_2 100]
file [client] [open_dir_2 100]
dir [abc] [open_dir_2 96]
file [yasm-1.3.0.tar.gz] [open_dir_2 100]
file [output.yuv] [open_dir_2 100]
file [mySDLFirst.out] [open_dir_2 100]
-++--+++--[main 118]
root@ubuntu:/share#