getdents - get directory entries in a filesystem independent format
Standard C Library (libc, -lc)
getdents(int fd, char *buf, size_t nbytes);
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 each containing
the following entries:
unsigned long d_fileno;
unsigned short d_reclen;
unsigned short d_namlen;
char d_name[MAXNAMLEN + 1]; /* see below */
The d_fileno entry is a number which is unique for each distinct file in
the filesystem. Files that are linked by hard links (see link(2)) have
the same d_fileno. If d_fileno is zero, the entry refers to a deleted
The d_reclen entry is the length, in bytes, of the directory record.
The d_name entry contains a null terminated file name.
The d_namlen entry specifies the length of the file name excluding the
null byte. Thus the actual size of d_name may vary from 1 to MAXNAMLEN +
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,
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.
If successful, the number of bytes actually transferred is returned.
Otherwise, -1 is returned and the global variable errno is set to indicate
getdents() will fail if:
[EBADF] fd is not a valid file descriptor open for reading.
[EFAULT] Either buf points outside the allocated address space.
[EIO] An I/O error occurred while reading from or writing to
the file system.
[EINVAL] A directory was being read on NFS, but it was modified
on the server while it was being read.
The getdents() function first appeared in NetBSD 1.3.
BSD June 9, 1993 BSD
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