NAME
getdirentries - gets directory entries in a filesystem independent
format

SYNOPSIS
#include <sys/dir.h>

cc = getdirentries(fd, buf, nbytes, basep)
int cc, fd;
char *buf;
int nbytes;
long *basep

DESCRIPTION
Getdirentries attempts to put 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). Sizes less than this
may cause errors on certain filesystems.

The data in the buffer is a series of direct structures each
containing the following entries:

unsigned long d_fileno;
unsigned short d_reclen;
unsigned short d_namlen;
char d_name[MAXNAMELEN + 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. 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. Thus the actual size of d_name may vary from 2
to (MAXNAMELEN + 1).

The structures are not necessarily tightly packed. The d_reclen
entry may be used as an offset from the beginning of a direct
structure to the next structure, if any.

Upon return, 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 is not necessarily
incremented by the number of bytes returned by getdirentries. If
the value returned is zero, the end of the directory has been
reached. The current position pointer may be set and retrieved by
lseek(2). Getdirentries writes the position of the block read into
the location pointed to by basep. It is not safe to set the
current position pointer to any value other than a value previously
returned by lseek(2) or a value previously returned in the location
pointed to by basep or zero.

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

SEE ALSO
open(2), lseek(2)

ERRORS
Getdirentries will fail if one or more of the following are true:

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

[EFAULT] Either buf or basep point outside the allocated
address space.

[EINTR] A read from a slow device was interrupted before any
data arrived by the delivery of a signal.

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