man.bsd.lv manual page server

Manual Page Search Parameters
DIRECTORY(3) Library Functions Manual DIRECTORY(3)

opendir, readdir, telldir, seekdir, rewinddir, closedir, dirfd — directory operations

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

DIR *
opendir(const char *filename);

struct dirent *
readdir(DIR *dirp);

long
telldir(const DIR *dirp);

void
seekdir(DIR *dirp, long loc);

void
rewinddir(DIR *dirp);

int
closedir(DIR *dirp);

int
dirfd(DIR *dirp);

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

The () function returns the current location associated with the named directory stream.

The () 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. Values returned by telldir() are good only for the lifetime of the DIR pointer, dirp, 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().

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

The () 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 () function 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(".");
while ((dp = readdir(dirp)) != NULL)
	if (dp->d_namlen == len && !strcmp(dp->d_name, name)) {
		(void)closedir(dirp);
		return FOUND;
	}
(void)closedir(dirp);
return NOT_FOUND;

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

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

BSD 4.2 June 4, 1993 DIRECTORY(3)