dirent(5) - NetBSD Manual Pages

Command: Section: Arch: Collection:  
DIRENT(5)                 NetBSD File Formats Manual                 DIRENT(5)


NAME
dirent -- directory format
SYNOPSIS
#include <sys/types.h> #include <sys/dirent.h>
DESCRIPTION
Directories provide a convenient hierarchical method of grouping files while obscuring the underlying details of the storage medium. A direc- tory file is differentiated from a plain file by a flag in its inode(5) entry. It consists of records (directory entries) each of which contains information about a file and a pointer to the file itself. Directory entries may contain other directories as well as plain files; such nested directories are referred to as subdirectories. A hierarchy of directo- ries and files is formed in this manner and is called a file system (or referred to as a file system tree). Each directory file contains two special directory entries; one is a pointer to the directory itself called dot `.' and the other a pointer to its parent directory called dot-dot `..'. Dot and dot-dot are valid pathnames, however, the system root directory `/', has no parent and dot- dot points to itself like dot. File system nodes are ordinary directory files on which has been grafted a file system object, such as a physical disk or a partitioned area of such a disk. (See mount(8).) The directory entry format is defined in the file <sys/dirent.h>: /* * A directory entry has a struct dirent at the front of it, containing * its inode number, the length of the entry, and the length of the name * contained in the entry. These are followed by the name padded to an * 8 byte boundary with null bytes. All names are guaranteed null * terminated. The maximum length of a name in a directory is MAXNAMLEN. */ struct dirent { ino_t d_fileno; /* file number of entry */ uint16_t d_reclen; /* length of this record */ uint8_t d_type; /* file type, see below */ uint8_t d_namlen; /* length of string in d_name */ #define MAXNAMLEN 511 char d_name[MAXNAMLEN + 1]; /* name must be no longer than this */ }; /* * File types */ #define DT_UNKNOWN 0 #define DT_FIFO 1 #define DT_CHR 2 #define DT_DIR 4 #define DT_BLK 6 #define DT_REG 8 #define DT_LNK 10 #define DT_SOCK 12 #define DT_WHT 14
SEE ALSO
getdents(2), fs(5), inode(5)
HISTORY
A dir structure appeared in Version 7 AT&T UNIX. The dirent structure appeared in NetBSD 1.3. NetBSD 5.0.1 June 22, 2007 NetBSD 5.0.1
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