directory(3)
NAME
opendir, readdir, telldir, seekdir, rewinddir, closedir − directory operations
SYNTAX
#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
The opendir subroutine opens the directory named by filename, associates a directory stream with it, 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 readdir subroutine 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 telldir subroutine returns the current location associated with the named directory stream.
The seekdir subroutine sets the position of the next readdir on the directory stream. The new position reverts to the one associated with the directory stream when the telldir 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 (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 rewinddir subroutine resets the position of the named directory stream to the beginning of the directory.
The closedir subroutine closes the named directory stream and frees the structure associated with the DIR pointer.
EXAMPLES
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;