m4_comment([$Id: txn.so,v 11.17 2003/10/18 19:16:24 bostic Exp $])

define(M4PAGELOCAL,)
include(tcl/m4.tcl)

m4_tcl_header(env txn, m4_tcl_txn, [dnl
env txn
	m4_tcl_arg([-nosync])
	m4_tcl_arg([-nowait])
	m4_tcl_arg([-parent txnid])
	m4_tcl_arg([-sync])
])

m4_p([dnl
The m4_tcl_txn command begins a transaction.  The returned transaction
handle is bound to a Tcl command of the form m4_bold(env.txnX), where
X is an integer starting at 0 (for example, env0.txn0 and env0.txn1).
It is through this Tcl command that the script accesses the transaction
methods.])

m4_p([dnl
The options are as follows:])

m4_tagbegin

m4_tag([-nosync], [dnl
Do not synchronously flush the log when this transaction commits or
prepares. This means the transaction will exhibit the ACI (atomicity,
consistency, and isolation) properties, but not D (durability); that
is, database integrity will be maintained, but it is possible that this
transaction may be undone during recovery instead of being redone.
m4_p([dnl
This behavior may be set for an entire m4_db environment as part of the
m4_tcl_env_open call.])])

m4_tag([-nowait], [dnl
If a lock is unavailable for any m4_db operation performed in the context
of this transaction, throw a Tcl error immediately instead of blocking on
the lock.])

m4_tag([-parent txnid], [dnl
Create the new transaction as a nested transaction, with the specified
transaction indicated as its parent.  Transactions may be nested to any
level.])

m4_tag([-sync], [dnl
Synchronously flush the log when this transaction commits or prepares.
This means the transaction will exhibit all of the ACID (atomicity,
consistency, isolation, and durability) properties.
m4_p([dnl
This behavior is the default for m4_db environments unless the
m4_arg(-nosync) option was specified to the m4_tcl_env_open call.])])

m4_tagend

m4_p([dnl
The m4_tcl_txn command returns a transaction handle on success.])

m4_tcl_ret_error

m4_page_footer