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

NAME
     ooppeennddiirr, rreeaaddddiirr, rreeaaddddiirrrr, tteellllddiirr, sseeeekkddiirr, rreewwiinnddddiirr, cclloosseeddiirr, ddiirrffdd
     - directory operations

LLIIBBRRAARRYY
     Standard C Library (libc, -lc)

SYNOPSIS
     ##iinncclluuddee <>
     ##iinncclluuddee <>

     DIR *
     ooppeennddiirr(const char *filename);

     struct dirent *
     rreeaaddddiirr(DIR *dirp);

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

     long
     tteellllddiirr(DIR *dirp);

     void
     sseeeekkddiirr(DIR *dirp, long loc);

     void
     rreewwiinnddddiirr(DIR *dirp);

     int
     cclloosseeddiirr(DIR *dirp);

     int
     ddiirrffdd(DIR *dirp);

DESCRIPTION
     The ooppeennddiirr() 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
     returned if filename cannot be accessed, or if it cannot malloc(3) enough
     memory to hold the whole thing.

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

     rreeaaddddiirrrr() provides the same functionality as rreeaaddddiirr(), 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.  rreeaaddddiirrrr() returns 0 on success or
     an error number to indicate failure.

     The tteellllddiirr() function returns the current location associated with the
     named directory stream.  Values returned by tteellllddiirr() 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
     tteellllddiirr() will no longer be valid.

     The sseeeekkddiirr() function sets the position of the next rreeaaddddiirr() operation
     on the directory stream.  The new position reverts to the one associated
     with the directory stream when the tteellllddiirr() operation was performed.

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

     The cclloosseeddiirr() 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 ddiirrffdd() 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->dnamlen == len && !strcmp(dp->dname, name)) {
                           (void)closedir(dirp);
                           return FOUND;
                   }
           (void)closedir(dirp);
           return NOTFOUND;

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

HISTORY     The ooppeennddiirr(), rreeaaddddiirr(), tteellllddiirr(), sseeeekkddiirr(), rreewwiinnddddiirr(), cclloosseeddiirr(),
     and ddiirrffdd() functions appeared in 4.2BSD.

BSD                              June 4, 1993                              BSD