2.11BSD#431 - /usr/man/cat3/opendir.0

DIRECTORY(3)	    UNIX Programmer's Manual	     DIRECTORY(3)


NAME
     opendir, readdir, telldir, seekdir, rewinddir, closedir -
     directory operations

SYNOPSIS
     #include <sys/types.h>
     #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 opera-
     tions.  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 opera-
     tion 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.


Printed 11/26/99       September 24, 1985			1


DIRECTORY(3)	    UNIX Programmer's Manual	     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(5)


Printed 11/26/99       September 24, 1985			2