Ice::OperationMode

Overview

enum OperationMode

The OperationMode determines the retry behavior an invocation in case of a (potentially) recoverable error.

Used By

• Ice::Current::mode

Enumerator Index

Normal — Ordinary operations have Normal mode.
Nonmutating — Operations that use the Slice nonmutating keyword must not modify object state.
Idempotent — Operations that use the Slice idempotent keyword can modify object state, but invoking an operation twice in a row must result in the same object state as invoking it once.

Enumerators

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Normal Normal

Normal

Ordinary operations have Normal mode. These operations modify object state; invoking such an operation twice in a row has different semantics than invoking it once. The Ice run time guarantees that it will not violate at-most-once semantics for Normal operations.

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Nonmutating Nonmutating

Nonmutating

Operations that use the Slice nonmutating keyword must not modify object state. For C++, nonmutating operations generate const member functions in the skeleton. In addition, the Ice run time will attempt to transparently recover from certain run-time errors by re-issuing a failed request and propagate the failure to the application only if the second attempt fails.

Nonmutating is deprecated; Use the idempotent keyword instead. For C++, to retain the mapping of nonmutating operations to C++ const member functions, use the ["cpp:const"] metadata directive.

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Idempotent Idempotent

Idempotent

Operations that use the Slice idempotent keyword can modify object state, but invoking an operation twice in a row must result in the same object state as invoking it once. For example, x = 1 is an idempotent statement, whereas x += 1 is not. For idempotent operations, the Ice run-time uses the same retry behavior as for nonmutating operations in case of a potentially recoverable error.