Copyright (c) 1983 Regents of the University of California.
All rights reserved.

Redistribution and use in source and binary forms are permitted
provided that the above copyright notice and this paragraph are
duplicated in all such forms and that any documentation,
advertising materials, and other materials related to such
distribution and use acknowledge that the software was developed
by the University of California, Berkeley. The name of the
University may not be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

@(#)directory.3 6.4 (Berkeley) 08/03/88

C 5 opendir, readdir, telldir, seekdir, rewinddir, closedir, dirfd - directory operations #include <sys/types.h>

#include <sys/dir.h>

DIR *opendir(filename)

char *filename;

struct direct *readdir(dirp)

DIR *dirp;

long telldir(dirp)

DIR *dirp;

seekdir(dirp, loc)

DIR *dirp;

long loc;

rewinddir(dirp)

DIR *dirp;

closedir(dirp)

DIR *dirp;

dirfd(dirp)

DIR *dirp;

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 malloc (3) enough memory to hold the whole thing.

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 may be invalidated due to undetected directory compaction. It is safe to use a previous telldir value immediately after a call to opendir and before any calls to readdir.

Rewinddir resets the position of the named directory stream to the beginning of the directory.

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

Dirfd returns the integer file descriptor associated with the named directory stream, see open(2).

Sample code which searchs a directory for entry ``name'' is:

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;

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