tdb_chainlock(3) [centos man page]

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

NAME

       tdb_chainlock - lock a group of keys tdb_chainunlock - unlock a previously locked group of keys

SYNOPSIS

       #include <tdb.h>

       int tdb_chainlock(TDB_CONTEXT *tdb, TDB_DATA key);
       void tdb_chainunlock(TDB_CONTEXT *tdb, TDB_DATA key);

DESCRIPTION

       tdb_chainlock  is  a  low-level function used to lock a particular key (and a number of other keys) without any checking: any other process
       attempting to perform tdb operations on those keys will block until tdb_chainunlock is called.

NOTES

       It is the user's responsibility to ensure that they do not deadlock the database using these functions: something which is impossible using
       the other access functions.

RETURN VALUE

       A return value of 0 indicates success and -1 indicates failure.

AUTHORS

       Software: Andrew Tridgell <tridge@linuxcare.com> Man page: Rusty.

SEE ALSO

       gdbm(3), tdb(3), tdb_lockall(3).

Samba								   Oct 13, 2000 						  TDB_CHAINLOCK(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)