---
title: "ClikaRT::runtime::PhaseSpec"
sidebar_label: "PhaseSpec"
description: "One declared phase of a model. name is borrowed; it must point into storage the model keeps alive (e.g. a static string or a member), matching the internal \"model owns the name\" contract."
---

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<span class="api-kind api-kind--struct">struct</span>

**Header:** `ClikaRT/runtime/schema.h`

One declared phase of a model. [`name`](./PhaseSpec.md#name) is borrowed; it must point into storage the model keeps alive (e.g. a static string or a member), matching the internal "model owns the name" contract.

A phase may carry its body as a callable instead of an override: a `RunOnce` phase set with [`run_once`](./PhaseSpec.md#run_once), an `Iterate` phase set with [`iterate`](./PhaseSpec.md#iterate). [`FunctionModel`](./FunctionModel.md) dispatches to these so a casual model needs no subclass at all (the callable runs caller-side, contained exactly like a [`Model`](./Model.md) override). A hand-written [`Model`](./Model.md) ignores them and overrides `Phase_RunOnce` / `Phase_Iterate` directly.

## Data members

### name {#name}

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`std::string_view` **`name`**

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phase name; unique within the model

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Declared in `ClikaRT/runtime/schema.h`, line 40

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### kind {#kind}

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[`PhaseKind`](./index.md#PhaseKind) **`kind`** `=` [`PhaseKind::RunOnce`](./index.md#PhaseKind)

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execution shape: run once vs iterate per step

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Declared in `ClikaRT/runtime/schema.h`, line 41

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### run\_once {#run_once}

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`std::function<void(`[`PhaseContext`](./PhaseContext.md) `&)>` **`run_once`**

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body for a RunOnce phase (optional)

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Declared in `ClikaRT/runtime/schema.h`, line 42

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### iterate {#iterate}

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`std::function<`[`StepBatchOut`](./StepBatchOut.md)`(`[`StepContext`](./StepContext.md) `&)>` **`iterate`**

</div>

body for an Iterate phase (optional)

<div class="api-declared">

Declared in `ClikaRT/runtime/schema.h`, line 43

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