opendarwin man page for getdirentries

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

NAME
     getdirentries -- get directory entries in a filesystem independent format

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

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

DESCRIPTION
     Getdirentries() 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 getdirentries() with buffers smaller than this size.

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

	   u_int32_t	   d_fileno;		 /* file number of entry */
	   u_int16_t	   d_reclen;		 /* length of this record */
	   u_int8_t	   d_type;		 /* file type, see below */
	   u_int8_t	   d_namlen;		 /* length of string in d_name */
	   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.  Users of getdirentries() should skip entries with d_fileno = 0, as such entries represent files which have been
     deleted but not yet removed from the directory entry.  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 MAXNAMELEN + 1.	d_type is a integer representing the type of the directory entry.  The following types are
     defined in <sys/dirent.h>:

	   #define DT_UNKNOWN	    0
	   #define DT_FIFO	    1
	   #define DT_CHR	    2
	   #define DT_DIR	    4
	   #define DT_BLK	    6
	   #define DT_REG	    8
	   #define DT_LNK	   10
	   #define DT_SOCK	   12
	   #define DT_WHT	   14

     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 struc-
     ture, 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().	A value of zero is returned when the end of the
     directory has been reached.

     Getdirentries() 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.

ERRORS
     Getdirentries() 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
     open(2), lseek(2)

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

BSD
								   June 9, 1993 							       BSD