DIRECTORY(3)

NAME
opendir, readdir, telldir, seekdir, rewinddir, closedir - directory operations

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

DIR *opendir(filename)
char *filename;

struct dirent *readdir(dirp)
DIR *dirp;

long telldir(dirp)
DIR *dirp;

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

rewinddir(dirp)
DIR *dirp;

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 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.

Sample code which searches 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;

NOTES

The directory() library routines now use a new include file, <dirent.h>. This replaces the file, <sys/dir.h>, used in previous releases. Furthermore, with the use of this new file, the readdir() routine returns directory entries whose structure is named struct dirent rather than struct direct as before. The file, <sys/dir.h>, is not retained in the current NFSSRC release, so programs which use the directory() library and the file, <sys/dir.h>, will fail to compile and run without source code modifications.

SEE ALSO
open(2), close(2), read(2), lseek(2), malloc(3), dir(5)