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

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

     Standard C Library (libc, -lc)

     #include <dirent.h>

     closedir(DIR *dirp);

     dirfd(DIR *dirp);

     DIR *
     opendir(const char *dirname);

     struct dirent *
     readdir(DIR *dirp);

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

     rewinddir(DIR *dirp);

     seekdir(DIR *dirp, long loc);

     telldir(DIR *dirp);

     The opendir() function opens the directory named by dirname, 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
     returned if dirname cannot be accessed or if it cannot malloc(3) enough
     memory to hold the whole thing.

     The readdir() function returns a pointer to the next directory entry.  It
     returns NULL upon reaching the end of the directory or detecting an
     invalid seekdir() operation.

     readdir_r() 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.  readdir_r() returns 0 on success
     or an error number to indicate failure.

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

     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 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:

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

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

     <sys/types.h> is necessary for these functions.

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

     The closedir(), dirfd(), opendir(), readdir(), rewinddir(), seekdir(),
     and telldir() functions appeared in 4.2BSD.

BSD                              June 4, 1993                              BSD