m4_comment([$Id: db_upgrade.so,v 10.37 2004/08/13 03:38:56 bostic Exp $])

define(M4PAGELOCAL, [dbh_upgrade, DB_DUPSORT])
include(m4/m4.seealso)

m4_pf_header(m4_ref(dbh_upgrade),
ifelse(M4API, C_API, [dnl
int
DB-__GT__upgrade(DB *db, const char *file, u_int32_t flags);
])
ifelse(M4API, CXX_API, [dnl
int
Db::upgrade(const char *file, u_int32_t flags);
]))

m4_p([dnl
The m4_refT(dbh_upgrade) upgrades all of the databases included in the
file m4_arg(file), if necessary.  If no upgrade is necessary,
m4_ref(dbh_upgrade) always returns success.])

m4_p([m4_bold([dnl
Database upgrades are done in place and are destructive. For example,
if pages need to be allocated and no disk space is available, the
database may be left corrupted.  Backups should be made before databases
are upgraded.  See m4_link(M4RELDIR/ref/am/upgrade, Upgrading databases)
for more information.])])

m4_p([dnl
Unlike all other database operations, m4_ref(dbh_upgrade) may only be done
on a system with the same byte-order as the database.])

m4_return(dbh_upgrade, std)

m4_underfunc(dbh_upgrade, dbh_upgrade, db_upgrade)

m4_parambegin
m4_param(file, [dnl
The m4_arg(file) parameter is the physical file containing the databases
to be upgraded.])

m4_param(flags, [dnl
m4_sf_zmust(0)

m4_tagbegin
m4_tag(m4_idef(DB_DUPSORT), [dnl
m4_bold([This flag is only meaningful when upgrading databases from
releases before the m4_db 3.1 release.])
m4_p([dnl
As part of the upgrade from the m4_db 3.0 release to the 3.1 release,
the on-disk format of duplicate data items changed.  To correctly
upgrade the format requires applications to specify whether duplicate
data items in the database are sorted or not.  Specifying the
m4_ref(DB_DUPSORT) flag informs m4_ref(dbh_upgrade) that the duplicates
are sorted; otherwise they are assumed to be unsorted.  Incorrectly
specifying the value of this flag may lead to database corruption.])
m4_p([dnl
Further, because the m4_refT(dbh_upgrade) upgrades a physical file
(including all the databases it contains), it is not possible to use
m4_ref(dbh_upgrade) to upgrade files in which some of the databases it
includes have sorted duplicate data items, and some of the databases it
includes have unsorted duplicate data items.  If the file does not have
more than a single database, if the databases do not support duplicate
data items, or if all of the databases that support duplicate data items
support the same style of duplicates (either sorted or unsorted),
m4_ref(dbh_upgrade) will work correctly as long as the
m4_ref(DB_DUPSORT) flag is correctly specified.  Otherwise, the file
cannot be upgraded using m4_ref(dbh_upgrade); it must be upgraded
manually by dumping and reloading the databases.])])

m4_tagend])
m4_paramend

m4_header([Environment Variables])
m4_data_location(dbh_upgrade, 1)

m4_err(dbh_upgrade,
m4_idef(DB_OLD_VERSION),
[The database cannot be upgraded by this version of the m4_db software.],
einval, [the database is not in the same byte-order as the system])

m4_seealso(Db)
m4_page_footer