tdb_traverse(3) [debian man page]

TDB_TRAVERSE(3) 					     Linux Programmer's Manual						   TDB_TRAVERSE(3)

NAME

       tdb_traverse - visit every element in a tdb database

SYNOPSIS

       #include <tdb.h>

       int tdb_traverse(TDB_CONTEXT *tdb,
	       int (*fn)(TDB_CONTEXT *,TDB_DATA,TDB_DATA,void *),
	       void *state);

DESCRIPTION

       tdb_traverse  is  the only sure way to visit all the items within a given database, tdb Because this function has intimate knowledge of the
       internals of the database, it is able to cope with writers touching the database at the same time it is trying to traverse it.

       If fn is supplied it will be called with the state parameter for each element in the database, as the forth argument. The First argument is
       the  database  tdb  the second is the key and the third is the data. If this function call returns anything but 0, the traversal will stop.
       Unlike in tdb_fetch() the programmer is not required to free either the pointer from either the key or data parameters that are passed into
       the function. The fn function should have the prototype:
	  int (*tdb_traverse_func)(TDB_CONTEXT *, TDB_DATA, TDB_DATA, void *);

       Calling tdb_traverse with a NULL fn parameter is the appropriate way to count the number of elements in the database.

RETURN VALUE

       The return value is the number of elements traversed or -1 if there was an error.

AUTHORS

       Software: Andrew Tridgell <tridge@linuxcare.com> and Luke Kenneth Casson Leighton Man page: Ben Woodard <ben@valinux.com>

SEE ALSO

       gdbm(3), tdb(3)

Samba								   Aug 16, 2000 						   TDB_TRAVERSE(3)

TDB_FIRSTKEY(3) 					     Linux Programmer's Manual						   TDB_FIRSTKEY(3)

NAME

       tdb_firstkey - return the key of the first record in a tdb database tdb_nextkey - return the key of next record in the tdb database

SYNOPSIS

       #include <tdb.h>

       TDB_DATA tdb_firstkey(TDB_CONTEXT *tdb);
       TDB_DATA tdb_nextkey(TDB_CONTEXT *tdb, TDB_DATA prev_key);

DESCRIPTION

       tdb_firstkey  fetches  the key of the first entry in the tdb database.  tdb_nextkey fetches the key of the entry immediately after prev_key
       in the database.

       The TDB_DATA structure returned by both these functions is defined as:

	      typedef struct {
		   char *dptr;
		   size_t dsize;
	      } TDB_DATA;

       The order in which this traverses the database is its own internal hash order. Do not expect the keys to  be  in  any  recognizably  sorted
       order.

       These  functions are reliable even if other writers are accessing the database (or you are replacing or deleting elements as you traverse),
       except in the case of nested tdb_firstkey or tdb_nextkey calls.	For example, the following outer traversal may fail to	traverse  all  the
       elements, or may even traverse elements twice if other processes are manipulating the database:

		   TDB_DATA i, j;

		   for (i = tdb_firstkey(tdb); i.dptr; i = tdb_nextkey(tdb, i)) {
			for (j = tdb_firstkey(tdb); j.dptr; j = tdb_nextkey(tdb, j)) {
			...
			}
		   }

       If such behaviour is desired, use tdb_traverse instead.

RETURN VALUE

       If  the	call  succeeds, then a TDB_DATA structure is returned with the dptr structure filled in. If the call fails or you have reached the
       end of the database then dptr will be set to NULL.

       NOTE: The caller is responsible for freeing the data pointed to by dptr

AUTHORS

       Software: Andrew Tridgell <tridge@linuxcare.com> and Luke Kenneth Casson Leighton Man page: Ben Woodard <ben@valinux.com>

SEE ALSO

       gdbm(3), tdb(3)

Samba								   Aug 16, 2000 						   TDB_FIRSTKEY(3)