---
title: Side effects
description: A summary of side effects in the Flux functional data scripting language.
url: https://docs.influxdata.com/flux/v0/spec/side-effects/
estimated_tokens: 93
product: Flux
version: v0
publisher: InfluxData
canonical: https://docs.influxdata.com/flux/v0/spec/side-effects/
date: '2023-09-12T23:33:31-06:00'
lastmod: '2023-09-12T23:33:31-06:00'
---

Side effects can occur in one of two ways.

1. By reassigning built-in options
2. By calling a function that produces side effects

A function produces side effects when it is explicitly declared to have side effects or when it calls a function that itself produces side effects.

[Statements](/flux/v0/spec/statements/)[System built-ins](/flux/v0/spec/system-built-ins/)