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Fault Tolerance Callback Function

When a process joins a fault tolerance group, it must specify a fault tolerance callback function as a parameter. The callback function must be defined by the program. When Rendezvous fault tolerance software detects any change that requires action by the program, it queues the callback function. It is not necessary that all members of a group have the same fault tolerance callback function.

Among its arguments, the callback function receives a token denoting an action—in this way Rendezvous fault tolerance software instructs the program how to behave in order to assure fault-tolerant operation. The callback function must comply with the action instruction by taking whatever steps are needed.

The action token may instruct an inactive member to activate; or it may instruct an active member to deactivate; or it may instruct an inactive member to prepare to activate (hinting that an instruction to activate might soon arrive).

For more information, see Fault Tolerance Callback Actions, and Program Callback Functions.

For information about callback closure arguments, see Closure Data.

Copyright © Cloud Software Group, Inc. All Rights Reserved