directory(3) directory(3)
NAME
opendir, readdir, telldir, seekdir, rewinddir, closedir -
directory operations
SYNOPSIS
#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;
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.
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directory(3) directory(3)
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 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;
SEE ALSO
open(2), close(2), read(2), lseek(2), dir(4).
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