GETDENTS(2)

NAME
getdents - get directory entries in a filesystem independent format

LIBRARY
libc

SYNOPSIS
#include <dirent.h>
int
getdents(int fd, char *buf, size_t nbytes);

DESCRIPTION
getdents() reads directory entries from the directory referenced by the file descriptor fd into the buffer pointed to by buf, in a filesystem independent format. Up to nbytes of data will be transferred. nbytes must be greater than or equal to the block size associated with the file, see stat(2). Some filesystems may not support getdents() with buffers smaller than this size.

The data in the buffer is a series of dirent structures:

    struct dirent {
    	ino_t	 d_fileno;		/* file number of entry */
    	uint16_t d_reclen;		/* length of this record */
    	uint16_t d_namlen;		/* length of d_name */
    	uint8_t  d_type;		/* file type, see below */
    	char	 d_name[MAXNAMELEN + 1];
    };

The structure is described in dirent(3).

Entries may be separated by extra space. The d_reclen entry may be used as an offset from the start of a dirent structure to the next structure, if any.

The actual number of bytes transferred is returned. The current position pointer associated with fd is set to point to the next block of entries. The pointer may not advance by the number of bytes returned by getdents(). A value of zero is returned when the end of the directory has been reached.

The current position pointer may be set and retrieved by lseek(2). The current position pointer should only be set to a value returned by lseek(2), or zero.

RETURN VALUES
If successful, the number of bytes actually transferred is returned. Otherwise, -1 is returned and the global variable errno is set to indicate the error.

ERRORS
getdents() will fail if:

[EBADF]
    fd is not a valid file descriptor open for reading.

[EFAULT]
    buf points outside the allocated address space.

[EINVAL]
    A directory was being read on NFS, but it was modified on the server while it was being read.

[EIO]
    An I/O error occurred while reading from or writing to the file system.

SEE ALSO
lseek(2), open(2), dirent(3)

HISTORY
The getdents() function first appeared in NetBSD 1.3.