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directory(3C)							 directory(3C)


NAME    [Toc]    [Back]

     directory:	opendir, readdir, readdir64, telldir, telldir64, seekdir,
     seekdir64,	rewinddir, closedir, readdir_r,	readdir64_r - directory
     operations

SYNOPSIS    [Toc]    [Back]

     #include <dirent.h>

     DIR *opendir (const char *filename);

     struct dirent *readdir (DIR *dirp);

     struct dirent64 *readdir64	(DIR *dirp);

     off_t telldir (DIR	*dirp);

     off64_t telldir64 (DIR *dirp);

     void seekdir (DIR *dirp, off_t loc);

     void seekdir64 (DIR *dirp,	off64_t	loc);

     void rewinddir (DIR *dirp);

     int closedir (DIR *dirp);

     int readdir_r (DIR	*dirp, struct dirent *entry, struct dirent **res);

     int readdir64_r (DIR *dirp, struct	dirent64 *entry, struct	dirent64
     **res);

DESCRIPTION    [Toc]    [Back]

     The inclusion of <dirent.h> selects the System V versions of these
     routines.	For the	4.3BSD versions, include <sys/dir.h>.  The 64-bit
     interfaces	are not	present	in the 4.3BSD versions.

     opendir opens the directory named by filename and associates a directory
     stream with it.  opendir returns a	pointer	to be used to identify the
     directory stream in subsequent operations.	 The directory stream is
     positioned	at the first entry.  A null pointer is returned	if filename
     cannot be accessed	or is not a directory, or if it	cannot malloc(3C)
     enough memory to hold a DIR structure or a	buffer for the directory
     entries.

     readdir returns a pointer to the next active directory entry and
     positions the directory stream at the next	entry.	No inactive entries
     are returned.  It returns NULL upon reaching the end of the directory or
     upon detecting an invalid location	in the directory.  readdir buffers
     several directory entries per actual read operation; readdir marks	for
     update the	st_atime field of the directory	each time the directory	is
     actually read.




									Page 1






directory(3C)							 directory(3C)



     readdir_r is a reentrant version of readdir.  The directory entry at the
     current position in dirp is copied	into entry.  The storage pointed to by
     entry shall be large enough for a dirent with an array of char d_NAME
     member containing at least	{NAME_MAX} plus	one elements.  Upon successful
     return, the pointer returned at *result shall have	the same value as the
     argument entry.  Upon reaching the	end of the directory stream, this
     pointer shall have	the value NULL.

     telldir returns the current location associated with the named directory
     stream.

     seekdir sets the position of the next readdir operation on	the directory
     stream.  The new position reverts to the position associated with the
     directory stream at the time the telldir operation	that provides loc was
     performed.	 Values	returned by telldir are	valid only if the directory
     has not changed because of	compaction or expansion.  This situation is
     not a problem with	System V, but it may be	a problem with some file
     system types.

     rewinddir resets the position of the named	directory stream to the
     beginning of the directory.  It also causes the directory stream to refer
     to	the current state of the corresponding directory, as a call to opendir
     would.

     closedir closes the named directory stream	and frees the DIR structure.

     readdir64,	readdir64_r, seekdir64,	and telldir64 are parallel interfaces
     provided for cases	where the information returned will not	fit in the
     fields in the dirent structure.  The fields in question are the inode
     number (d_ino) and	the current offset (d_off).  If	it is necessary	to
     call the 64-bit interfaces, and they are not called, an EOVERFLOW error
     will result.  The 64-bit readdir and telldir interfaces should not	be
     mixed with	the non-64-bit interfaces in a sequence	of calls.

     The following errors can occur as a result	of these operations.

     opendir returns NULL on failure and sets errno to one of the following
     values:

     ENOTDIR		 A component of	filename is not	a directory.

     EACCES		 A component of	filename denies	search permission.

     EACCES		 Read permission is denied on the specified directory.

     EMFILE		 The maximum number of file descriptors	are currently
			 open.

     ENFILE		 The system file table is full.






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directory(3C)							 directory(3C)



     EFAULT		 filename points outside the allocated address space.

     ELOOP		 Too many symbolic links were encountered in
			 translating filename.

     ENAMETOOLONG	 The length of the filename argument exceeds
			 {PATH_MAX}, or	the length of a	filename component
			 exceeds {NAME_MAX} while {_POSIX_NO_TRUNC} is in
			 effect.

     ENOENT		 A component of	filename does not exist	or is a	null
			 pathname.

     readdir returns NULL on failure and sets errno to one of the following
     values:

     ENOENT		 The current file pointer for the directory is not
			 located at a valid entry.

     EBADF		 The file descriptor determined	by the DIR stream is
			 no longer valid.  This	result occurs if the DIR
			 stream	has been closed.

     EDIRCORRUPTED	 The directory is corrupted on disk.

     EOVERFLOW		 One of	the inode number values	or offset values did
			 not fit in 32 bits, and the 64-bit interfaces were
			 not used.

     EINVAL		 64-bit	and non-64-bit calls were mixed	in a sequence
			 of calls.

     readdir_r returns 0 on success and	an error value (see above values for
     readdir) on error.

     telldir, seekdir, and  closedir return -1 on failure and set errno	to the
     following value:

     EBADF		 The file descriptor determined	by the DIR stream is
			 no longer valid.  This	results	if the DIR stream has
			 been closed.

     EINVAL		 64-bit	and non-64-bit calls were mixed	in a sequence
			 of calls.

EXAMPLE    [Toc]    [Back]

     Here is a sample program that prints the names of all the files in	the
     current directory:

	  #include <stdio.h>
	  #include <dirent.h>




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directory(3C)							 directory(3C)



	  main()
	  {
	       DIR *dirp;
	       struct dirent *direntp;

	       dirp = opendir( "." );
	       while ( (direntp	= readdir( dirp	)) != NULL )
		    (void)printf( "%s\n", direntp->d_name );
	       closedir( dirp );
	       return (0);
	  }

SEE ALSO    [Toc]    [Back]

      
      
     getdents(2), mkdir(2), rmdir(2), malloc(3C), scandir(3C), dirent(4),
     directory_bsd(3B).

NOTES    [Toc]    [Back]

     These functions overwrite the buffer as needed, so	applications should
     copy data to preserve it.

     The telldir() and seekdir() functions used	long in	place of off_t prior
     to	IRIX 6.2.  This	change makes no	difference in the o32 and 64 bit
     compilation environments, but in the n32 compilation environment source
     that used to use a	long may need to be changed to use an off_t instead.

BUGS    [Toc]    [Back]

     The prototypes for	telldir() and seekdir()	in dirent.h use	long rather
     than off_t	in the o32 and 64 bit compilation environments.	 This is
     harmless, however,	because	long and off_t are identical in	these
     environments.


									PPPPaaaaggggeeee 4444
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