DIRECTORY(3B)DIRECTORY(3B)NAME
opendir, readdir, telldir, seekdir, rewinddir, closedir, dirfd-
directory operations (4.3BSD)
SYNOPSIS
#include <sys/types.h>
#include <sys/dir.h>
DIR *opendir(char *filename);
struct direct *readdir(DIR *dirp);
long telldir(DIR *dirp);
void seekdir(DIR *dirp, long loc);
void rewinddir(DIR *dirp);
void closedir(DIR *dirp);
int dirfd(DIR *dirp)
DESCRIPTION
The inclusion of <sys/dir.h> selects the 4.3BSD versions of these
routines. For the System V versions, include <dirent.h>.
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.
Page 1
DIRECTORY(3B)DIRECTORY(3B)
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 that searches a directory for entry ``name'':
len = strlen(name);
dirp = opendir(".");
if (dirp == NULL) {
return NOT_FOUND;
}
while ((dp = readdir(dirp)) != NULL) {
if (dp->d_namlen == len && !strcmp(dp->d_name, name)) {
closedir(dirp);
return FOUND;
}
}
closedir(dirp);
return NOT_FOUND;
SEE ALSOopen(2), close(2), read(2), lseek(2), directory(3C)
Page 2
