dbinfo.so

berkeley db 4.6.21的源码。berkeley db是一个简单的数据库管理系统

m4_comment([$Id: dbinfo.so,v 11.10 2001/04/03 19:39:02 bostic Exp $])

m4_ref_title(Upgrading m4_db Applications,
    Release 3.0: the DBINFO structure,, upgrade.3.0/db, upgrade.3.0/join)

m4_p([dnl
The DB_INFO structure has been removed from the m4_db 3.0 release.
Accesses to any fields within that structure by the application should be
replaced with method calls on the m4_ref(Db) handle.  The following
example illustrates this using the historic db_cachesize structure field.
In the m4_db 2.X releases, applications could set the size of an
underlying database cache using code similar to the following:])

m4_indent([dnl
DB_INFO dbinfo;
m4_blank
	memset(dbinfo, 0, sizeof(dbinfo));
	dbinfo.db_cachesize = 1024 * 1024;])

m4_p([dnl
in the m4_db 3.X releases, this should be done using the
m4_ref(dbh_set_cachesize) method, as follows:])

m4_indent([dnl
DB *db;
int ret;
m4_blank
	ret = db-__GT__set_cachesize(db, 0, 1024 * 1024, 0);])

m4_p([dnl
The DB_INFO structure is no longer used in any way by the m4_db 3.0
release, and should be removed from the application.])

m4_p([dnl
The following table lists the DB_INFO fields previously used by
applications and the methods that should now be used to set
them.  Because these calls provide configuration for the
database open, they must precede the call to m4_ref(dbh_open).
Calling them after the call to m4_ref(dbh_open) will return an
error.])

m4_table_begin(, _center)
m4_table_header(DB_INFO field, m4_db 3.X method)
m4_table_element(bt_compare, m4_ref(dbh_set_bt_compare))
m4_table_element(bt_minkey, m4_ref(dbh_set_bt_minkey))
m4_table_element(bt_prefix, m4_ref(dbh_set_bt_prefix))

m4_table_element(db_cachesize,
[m4_ref(dbh_set_cachesize)
m4_p([dnl
Note: the m4_ref(dbh_set_cachesize) function takes additional arguments.
Setting both the second argument (the number of GB in the pool) and the
last argument (the number of memory pools to create) to 0 will result in
behavior that is backward-compatible with previous m4_db releases.])])

m4_table_element(db_lorder, m4_ref(dbh_set_lorder))
m4_table_element(db_malloc, DB-__GT__set_malloc)
m4_table_element(db_pagesize, m4_ref(dbh_set_pagesize))
m4_table_element(dup_compare, m4_ref(dbh_set_dup_compare))

m4_table_element(flags,
[m4_ref(dbh_set_flags)
m4_p([dnl
Note: the DB_DELIMITER, DB_FIXEDLEN and DB_PAD flags no longer need to be
set as there are specific methods off the m4_ref(Db) handle that set the
file delimiter, the length of fixed-length records and the fixed-length
record pad character.  They should simply be discarded from the application.])])

m4_table_element(h_ffactor, m4_ref(dbh_set_h_ffactor))
m4_table_element(h_hash, m4_ref(dbh_set_h_hash))
m4_table_element(h_nelem, m4_ref(dbh_set_h_nelem))
m4_table_element(re_delim, m4_ref(dbh_set_re_delim))
m4_table_element(re_len, m4_ref(dbh_set_re_len))
m4_table_element(re_pad, m4_ref(dbh_set_re_pad))
m4_table_element(re_source, m4_ref(dbh_set_re_source))
m4_table_end

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