tdb_writelock(Aug 16, 2000)	      tdb_writelock(Aug 16, 2000)


NAME
       tdb_writelock - lock the database for writing.  tdb_write-
       unlock - unlock a previously locked database tdb_chainlock
       - lock a hash chain for writing tdb_chainunlock - unlock a
       previousl unlocked chain

SYNOPSIS
       #include <tdb.h>

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


DESCRIPTION
       NOTE: To be really honest, I have no idea why  these  when
       functions  are necessary. From what I can see tdb does all
       locking automatically now. My only  guess  is  that  these
       functions  are  either  not  supposed  to  be  part of the
       exposed API or they are depricated.

       tdb_writelock locks the entire database	and  tdb_writeun-
       lock  unlocks  the database. This function does not appear
       to be necessary in the current version of TDB.

       In tdb keys are kept on hash chains. At any given time  an
       unknown number of keys may be on any given hash chain. The
       intent of tdb_chainlock is to reduce  contention  for  the
       global  writelock  by  making  the  locks  finer  grained.
       tdb_chainlock locks the hash chain on which the index  key
       exists.	 tdb_chainunlock  unlocks  a  particular chain of
       records. This function does not appear to be necessary  in
       the current version of TDB.

       The TDB_DATA structure pointed to by key is defined as:

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


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

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

SEE ALSO
       gdbm(3), tdb(3)



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