DIRECTORY(3)
NAME
opendir, readdir, telldir, seekdir, rewinddir, closedir − directory operations
USAGE
#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 identify the directory stream in subsequent operations. The pointer NULL is returned if filename cannot be accessed, or if malloc(3) cannot allocate enough memory to hold the entire DIR structure.
Readdir returns a pointer to the next directory entry. It returns NULL upon reaching the end of the directory, or upon detecting an invalid seekdir operation.
Telldir returns the current location associated with 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, because of 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.
EXAMPLE
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;