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DIRECTORY(3)		 BSD Library Functions Manual		  DIRECTORY(3)

     opendir, fdopendir, readdir, readdir_r, telldir, seekdir, rewinddir,
     closedir, fdclosedir, dirfd -- directory operations

     Standard C	Library	(libc, -lc)

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

     DIR *
     opendir(const char	*filename);

     DIR *
     fdopendir(int fd);

     struct dirent *
     readdir(DIR *dirp);

     readdir_r(DIR *dirp, struct dirent	*entry,	struct dirent **result);

     telldir(DIR *dirp);

     seekdir(DIR *dirp,	long loc);

     rewinddir(DIR *dirp);

     closedir(DIR *dirp);

     fdclosedir(DIR *dirp);

     dirfd(DIR *dirp);

     The opendir() function opens the directory	named by filename, associates
     a directory stream	with it	and returns a pointer to be used to identify
     the directory stream in subsequent	operations.  The pointer NULL is re-
     turned if filename	cannot be accessed, or if it cannot malloc(3) enough
     memory to hold the	whole thing.

     The fdopendir() function is equivalent to the opendir() function except
     that the directory	is specified by	a file descriptor fd rather than by a
     name.  The	file offset associated with the	file descriptor	at the time of
     the call determines which entries are returned.

     Upon successful return from fdopendir(), the file descriptor is under the
     control of	the system, and	if any attempt is made to close	the file de-
     scriptor, or to modify the	state of the associated	description other than
     by	means of closedir(), readdir(),	readdir_r(), or	rewinddir(), the be-
     havior is undefined.  Upon	calling	closedir() the file descriptor is
     closed.  The FD_CLOEXEC flag is set on the	file descriptor	by a success-
     ful call to fdopendir().

     The readdir() function returns a pointer to the next directory entry.  It
     returns NULL upon reaching	the end	of the directory or on error.  In the
     event of an error,	errno may be set to any	of the values documented for
     the getdirentries(2) system call.

     The readdir_r() function provides the same	functionality as readdir(),
     but the caller must provide a directory entry buffer to store the results
     in.  If the read succeeds,	result is pointed at the entry;	upon reaching
     the end of	the directory result is	set to NULL.  The readdir_r() function
     returns 0 on success or an	error number to	indicate failure.

     The telldir() function returns a token representing the current location
     associated	with the named directory stream.  Values returned by telldir()
     are good only for the lifetime of the DIR pointer,	dirp, from which they
     are derived.  If the directory is closed and then reopened, prior values
     returned by telldir() will	no longer be valid.  Values returned by
     telldir() are also	invalidated by a call to rewinddir().

     The seekdir() function sets the position of the next readdir() operation
     on	the directory stream.  The new position	reverts	to the one associated
     with the directory	stream when the	telldir() operation was	performed.

     The rewinddir() function resets the position of the named directory
     stream to the beginning of	the directory.

     The closedir() function closes the	named directory	stream and frees the
     structure associated with the dirp	pointer, returning 0 on	success.  On
     failure, -1 is returned and the global variable errno is set to indicate
     the error.

     The fdclosedir() function is equivalent to	the closedir() function	except
     that this function	returns	directory file descriptor instead of closing

     The dirfd() function returns the integer file descriptor associated with
     the named directory stream, see open(2).

     Sample code which searches	a directory for	entry ``name'' is:

	   dirp	= opendir(".");
	   if (dirp == NULL)
		   return (ERROR);
	   len = strlen(name);
	   while ((dp =	readdir(dirp)) != NULL)	{
		   if (dp->d_namlen == len && strcmp(dp->d_name, name) == 0) {
			   return (FOUND);
	   return (NOT_FOUND);

     close(2), lseek(2), open(2), read(2), dir(5)

     The opendir(), readdir(), telldir(), seekdir(), rewinddir(), closedir(),
     and dirfd() functions appeared in 4.2BSD.	The fdopendir()	function ap-
     peared in FreeBSD 8.0.  fdclosedir() function appeared in FreeBSD 10.0.

     The invalidation of telldir() tokens when calling seekdir() is non-stan-

BSD				 July 28, 2014				   BSD


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