DIRECTORY(3) BSD DIRECTORY(3)
NAME
opendir, opendir_r, readdir, readdir_r, telldir, seekdir, rewinddir,
closedir - directory operations
SYNOPSIS
#include <sys/types.h>
#include <sys/dir.h>
DIR *opendir(filename)
char *filename;
int opendir_r (dir_name, dir_pointer)
const char *dir_name;
DIR *dir_pointer;
struct direct *readdir(dirp)
DIR *dirp;
int readdir_r (dir_pointer, result)
DIR *dir_pointer;
struct dirent *result;
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 that 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;
NOTES
The opendir_r and readdir_r functions are the reentrant versions of the
opendir and readdir functions, respectively. The opendir_r function
stores the new directory stream associated with dir_name at dir_pointer.
The readdir_r function stores the next directory entry at result.
Upon successful completion, the opendir_r function returns 0 (zero).
Otherwise, -1 is returned.
Upon successful completion, the readdir_r function returns 0 (zero).
Otherwise, -1 is returned.
SEE ALSO
open(2), close(2), read(2), lseek(2), dir(5)