NAME

       getdirentries, getdents — get directory entries in a file system independent format

LIBRARY

       Standard C Library (libc, -lc)

SYNOPSIS

       #include <sys/types.h>
       #include <dirent.h>

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

       int
       getdents(int fd, char *buf, int nbytes);

DESCRIPTION

       The  getdirentries()  and getdents() system calls read directory entries from the directory referenced by
       the file descriptor fd into the buffer pointed to by buf, in a file system  independent  format.   Up  to
       nbytes  of data will be transferred.  The nbytes argument must be greater than or equal to the block size
       associated with the file, see stat(2).  Some file systems may not support these system calls with buffers
       smaller than this size.

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

             uint32_t d_fileno;
             uint16_t d_reclen;
             uint8_t  d_type;
             uint8_t  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 file system.  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_type entry is the type of the file pointed to by the directory record.
       The file type values are defined in <sys/dirent.h>.  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 MAXNAMELEN + 1.

       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  getdirentries()  or  getdents().   A value of zero is returned when the end of the directory has been
       reached.

       The getdirentries() system call writes the position of the block read into the  location  pointed  to  by
       basep.   Alternatively,  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), a value  returned  in  the  location
       pointed to by basep (getdirentries() only) 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

       The getdirentries() system call will fail if:

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

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

       [EINVAL]           The file referenced by fd is not a directory, or nbytes is too small for  returning  a
                          directory entry or block of entries, or the current position pointer is invalid.

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

SEE ALSO

       lseek(2), open(2)

HISTORY

       The  getdirentries()  system call first appeared in 4.4BSD.  The getdents() system call first appeared in
       FreeBSD 3.0.

Debian                                             May 3, 1995                                  GETDIRENTRIES(2)