m4_comment([$Id: db_exists.so,v 1.1 2007/07/12 18:27:42 bostic Exp $])

define(M4PAGELOCAL, dbh_exists)
include(m4/m4.seealso)

m4_pf_header(m4_ref(dbh_exists),
ifelse(M4API, C_API, [dnl
int
DB-__GT__exists(DB *db, DB_TXN *txnid, DBT *key, u_int32_t flags);
])
ifelse(M4API, CXX_API, [dnl
int
Db::exists(DbTxn *txnid, Dbt *key, u_int32_t flags);
]))

m4_p([dnl
The m4_refT(dbh_exists) returns if the specified key appears in the
database.])

m4_return(dbh_exists,
specific, DB_NOTFOUND, [if the specified key is not in the database],
specific, DB_KEYEMPTY, [if the database is a Queue or Recno database and
the specified key exists, but was never explicitly created by the
application or was later deleted], prev)

m4_parambegin
m4_param(flags, [dnl
m4_sf_zmust(1)

m4_sf_or_add(1)

m4_tagbegin
m4_tag(m4_idef(DB_READ_COMMITTED), [dnl
Configure a transactional read operation to have degree 2 isolation (the
read is not repeatable).])

m4_tag(m4_idef(DB_READ_UNCOMMITTED), [dnl
Configure a transactional read operation to have degree 1 isolation,
reading modified but not yet committed data.  Silently ignored if the
m4_ref(DB_READ_UNCOMMITTED) flag was not specified when the underlying
database was opened.])

m4_rmw_flag([Because the m4_refT(dbh_exists) will not hold locks across
m4_db calls in non-transactional operations, the m4_ref(DB_RMW) flag to
the m4_ref(dbh_exists) call is meaningful only in the presence of
transactions.])

m4_tagend])

m4_param_key
m4_param_txn(dbh_exists, ro)
m4_paramend

m4_seealso(Db)
m4_page_footer