getdirentries(2) [osx man page]

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

NAME

     getdirentries -- get directory entries in a filesystem independent format

SYNOPSIS

     #include <dirent.h>
     #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 (see dir(5))

     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.

NOTES

     getdirentries() should rarely be used directly; instead, opendir(3) and readdir(3) should be used.

     As of Mac OS X 10.6, getdirentries() is deprecated, and it is recommended that applications use readdir(3) rather than using getdirentries()
     directly.	Due to limitations with the system call, getdirentries() will not work with 64-bit inodes; in order to use getdirentries(),
     _DARWIN_NO_64_BIT_INODE must be defined.  See stat(2) for more information on _DARWIN_NO_64_BIT_INODE and its other effects.

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

     lseek(2), open(2), stat(2), opendir(3), readdir(3), dir(5)

HISTORY

     The getdirentries() function first appeared in 4.4BSD.

BSD
								   June 9, 1993 							       BSD

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getdirentries(2) System Calls Manual getdirentries(2)

Name
getdirentries - gets directory entries in a generic directory format

Syntax
#include <sys/dir.h>

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

Description
The system call puts directory entries from the directory referenced by the file descriptor fd into the buffer pointed to by buf, in a
generic directory format. Up to nbytes of data are transferred. The nbytes of data must be greater than or equal to the block size asso-
ciated with the file. For further information, see Sizes less than nbytes can cause errors on certain file systems.

The data returned in the buffer is a series of direct structures, each containing the following entries:
unsigned long d_ino;
unsigned short d_reclen;
unsigned short d_namlen;
char d_name[MAXNAMLEN + 1];

The d_ino entry is a number that is unique for each distinct file in the file system. Files that are linked by hard links have the same
d_ino . For further information, see The d_reclen entry is the length, in bytes, of the directory record. The d_namlen entry specifies
the length of the file name. The d_name entry contains a null-terminated file name. Thus, the actual size of d_name can vary from 2 to
MAXNAMLEN + 1.

The generic directory 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 If the value returned is zero, the
end of the directory has been reached. The current position pointer may be set and retrieved by The system call 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 pre-
viously returned by or a value previously returned in the location pointed to by basep or zero.

Return Values
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.

Diagnostics
The system call fails under the following conditions:

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

ENOTDIR The fd is not a directory.

EFAULT Either buf or basep points outside the allocated address space.

EIO While reading from or writing to the file system, an I/O error occurred.

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

EPERM The user does not have read permission in the directory. The system call is not the suggested interface for reading direc-
tories. The and routines offer a standard interface. See the reference page for information on these routines.

See Also
close(2), link(2), lseek(2), open(2), stat(2), directory(3)

getdirentries(2)

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getdirentries(2) [osx man page]

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