GETDIRENTRIES(2) BSD System Calls Manual GETDIRENTRIES(2)

NAME
     ggeettddiirreennttrriieess - get directory entries in a filesystem independent format

SYNOPSIS
     ##iinncclluuddee <>
     ##iinncclluuddee <>

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

DESCRIPTION
     GGeettddiirreennttrriieess() 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 ggeettddiirreennttrriieess() with
     buffers smaller than this size.

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

           uint32t       dfileno;             /* file number of entry */
           uint16t       dreclen;             /* length of this record */
           uint8t        dtype;               /* file type, see below */
           uint8t        dnamlen;             /* length of string in dname */
           char            dname[MAXNAMELEN + 1]; /* see below */

     The dfileno 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 dfileno.  Users of ggeettddiirreennttrriieess() should skip entries with
     dfileno = 0, as such entries represent files which have been deleted but
     not yet removed from the directory entry.  The dreclen entry is the
     length, in bytes, of the directory record.  The dname entry contains a
     null terminated file name.  The dnamlen entry specifies the length of
     the file name excluding the null byte.  Thus the actual size of dname
     may vary from 1 to MAXNAMELEN + 1.  dtype is a integer representing the
     type of the directory entry.  The following types are defined in
     :

           #define DTUNKNOWN       0
           #define DTFIFO          1
           #define DTCHR           2
           #define DTDIR           4
           #define DTBLK           6
           #define DTREG           8
           #define DTLNK          10
           #define DTSOCK         12
           #define DTWHT          14

     Entries may be separated by extra space.  The dreclen 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
     ggeettddiirreennttrriieess().  A value of zero is returned when the end of the direc-
     tory has been reached.

     GGeettddiirreennttrriieess() 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, 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 indi-
     cate the error.

EERRRROORRSS
     GGeettddiirreennttrriieess() will fail if:

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

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

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

SEE ALSO
     lseek(2), open(2)

HISTORY     The ggeettddiirreennttrriieess() function first appeared in 4.4BSD.

BSD                              June 9, 1993                              BSD