m4_comment([$Id: func.so,v 11.9 2001/03/01 15:58:20 bostic Exp $])

m4_ref_title(Upgrading m4_db Applications,
    Release 3.0: function arguments,, upgrade.3.0/envopen, upgrade.3.0/dbenv)

m4_p([dnl
In m4_db 3.0, there are no longer separate structures that represent
each subsystem (for example, DB_LOCKTAB or DB_TXNMGR), and an overall
m4_ref(DbEnv) environment structure.  Instead there is only the
m4_ref(DbEnv) structure.  This means that m4_ref(DbEnv) references
should be passed around by your application instead of passing around
DB_LOCKTAB or DB_TXNMGR references.])

m4_p([dnl
Each of the following functions:])

m4_indent([dnl
lock_detect
lock_get
lock_id
lock_put
lock_stat
lock_vec])

m4_p([dnl
should have its first argument, a reference to the DB_LOCKTAB structure,
replaced with a reference to the enclosing m4_ref(DbEnv) structure.  For
example, the following line of code from a m4_db 2.X application:])

m4_indent([dnl
DB_LOCKTAB *lt;
DB_LOCK lock;
	ret = lock_put(lt, lock);])

m4_p([dnl
should now be written as follows:])

m4_indent([dnl
DB_ENV *dbenv;
DB_LOCK *lock;
	ret = lock_put(dbenv, lock);])

m4_p([dnl
Similarly, all of the functions:])

m4_indent([dnl
log_archive
log_compare
log_file
log_flush
log_get
log_put
log_register
log_stat
log_unregister])

m4_p([dnl
should have their DB_LOG argument replaced with a reference to a
m4_ref(DbEnv) structure, and the functions:])

m4_indent([dnl
memp_fopen
memp_register
memp_stat
memp_sync
memp_trickle])

m4_p([dnl
should have their DB_MPOOL argument replaced with a reference to a
m4_ref(DbEnv) structure.])

m4_p([dnl
You should remove all references to DB_LOCKTAB, DB_LOG, DB_MPOOL, and
DB_TXNMGR structures from your application, they are no longer useful
in any way.  In fact, a simple way to identify all of the places that
need to be upgraded is to remove all such structures and variables
they declare, and then compile.  You will see a warning message from
your compiler in each case that needs to be upgraded.])

m4_page_footer