directory(3)                                         directory(3)



NAME
     opendir, readdir, telldir, seekdir,  rewinddir,  closedir  -
     perform operations on directories

SYNOPSIS
     #include <sys/types.h>
     #include <dirent.h> br #include <sys/dir.h>

     DIR *opendir(filename)
     char *filename;

     struct direct *readdir(dirp)
     DIR *dirp;

     long telldir(dirp)
     DIR *dir

     seekdir(dirp, loc)
     DIR *dirp
     long loc;

     void rewinddir(dirp)
     DIR *dirp;

     void closedir(dirp)
     DIR *dirp;

DESCRIPTION
     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 pointer NULL is returned if filename cannot
     be accessed, or if it cannot allocate enough memory to hold
     the entire file.

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

     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 one
     associated with the directory stream when the telldir
     operation was performed.  Values returned by telldir are
     good only for the lifetime of the DIR pointer from which
     they are derived.  If the directory is closed and then
     reopened, the telldir value can be invalidated because of
     undetected directory compaction.  It is safe to use a
     previous telldir value immediately after a call to opendir
     and before any calls to readdir.



January 1992                                                    1

directory(3)                                         directory(3)



     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
     directory.

     closedir closes the named directory stream and frees the
     structure associated with the DIR pointer.

EXAMPLES
     The following sample code searches a directory for an entry
     name:

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


     The result of using a directory stream after executing
     exec(2) is undefined.  After executing a fork(2), either the
     parent or the child (but not both) can continue processing
     the directory stream by using readdir or rewinddir, or both.

SEE ALSO
     close(2), getdirentries(2), lseek(2), open(2), read(2),
     dir(4)

     ls(1) in A/UX Command Reference






















2                                                    January 1992