af_transact(3)						    Attribute Filesystem (AtFS) 					    af_transact(3)

NAME

       af_transaction, af_commit, af_abort - a simple transaction mechanism for AtFS

SYNOPSIS

       #include <atfs.h>

       int af_transaction (void)

       int af_commit (void)

       int af_abort (void)

DESCRIPTION

       These functions implement a simple transaction mechanism for AtFS.  A transaction starts with calling af_transaction. All changes to exist-
       ing ASOs performed hereafter have no immediate permanent effect.  They rather get into effect, when  the  transaction  is  ended.   Calling
       af_commit  ends	the  transactions  and causes all changes to be saved to disk. af_abort aborts the transaction without saving the changes.
       These will then be discarded.

       Only modification of the state of existing source ASOs will be deferred. Creation or deletion of ASOs have immediate effect, regardless	if
       a  transaction  is  in  effect  or  not.  Additionally, all operations on derived ASOs (all operations on the derived object cache) are not
       affected by the transaction.

       All archive files that are to be changed when the transaction is finished are locked until the end of the transaction.  The  lock  prevents
       all  other  applications  to perform any modifications on the archive file. You should make sure, that ending a transaction should never be
       dependent on the successful termination of another application (deadlock danger).

DIAGNOSTICS

       Upon error, -1 is returned and af_errno is set to the corresponding error number.

BUGS

       Changes to the contents of busy versions have immediate effect.

AtFS-1.71						     Fri Jun 25 14:33:21 1993						    af_transact(3)