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directory(3)             BSD Library Functions Manual             directory(3)


NAME

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


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

     #include <dirent.h>

     int
     closedir(DIR *dirp);

     int
     dirfd(DIR *dirp);

     DIR *
     opendir(const char *dirname);

     struct dirent *
     readdir(DIR *dirp);

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

     void
     rewinddir(DIR *dirp);

     void
     seekdir(DIR *dirp, long loc);

     long
     telldir(DIR *dirp);


DESCRIPTION

     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.  In the event of an error,
     NULL is returned and errno will be set to reflect 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 on error.  In the
     event of an error, errno will 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() func-
     tion 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 on success, see open(2).  On failure, -1 is
     returned and the global variable errno is set to indicate the error.

     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) {
                           (void)closedir(dirp);
                           return (FOUND);
                   }
           }
           (void)closedir(dirp);
           return (NOT_FOUND);


LEGACY SYNOPSIS

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

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


SEE ALSO

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


HISTORY

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

BSD                              June 4, 1993                              BSD

Mac OS X 10.9.1 - Generated Tue Jan 7 09:12:05 CST 2014