Linux system programming files and I/O (iii) directory operations

I. Access to the directory

Function Description: Open a directory

Prototype: dir* Opendir (char *pathname);

return value:

Open success, return a directory pointer

Open failed, return null

Feature Description: Access the details of the next connection in the specified directory

Prototype: struct dirent* readdir (DIR *dirptr);

return value:

Returns a pointer to the dirent structure that contains the details of the next connection in the specified directory;

Returns NULL when no more connections

Feature Description: Closes a directory that is already open

Prototype: int Closedir (DIR *dirptr);

Return value: Call successfully returns 0, failure returns-1

Second, the directory information structure body

struct dirent
{
ino_t d_ino; /* inode number */
off_t d_off; /* offset to the next dirent */
unsigned short d_reclen; /* length of this record */
unsigned char d_type; /* type of file; not supported
by all file system types */
char d_name[256]; /* filename */
};