<p>The SimpleEscrow use case uses it:
<a href="https://playground.plutus.iohkdev.io/doc/haddock/plutus-use-cases/html/src/Plutus.Contracts.SimpleEscrow.html#refundEp" rel="nofollow noreferrer">https://playground.plutus.iohkdev.io/doc/haddock/plutus-use-cases/html/src/Plutus.Contracts.SimpleEscrow.html#refundEp</a></p>
<p>Another example is the Crowdfunding use case:
<a href="https://playground.plutus.iohkdev.io/doc/haddock/plutus-use-cases/html/src/Plutus.Contracts.Crowdfunding.html#contribute" rel="nofollow noreferrer">https://playground.plutus.iohkdev.io/doc/haddock/plutus-use-cases/html/src/Plutus.Contracts.Crowdfunding.html#contribute</a></p>

CC BY-SA 4.0
2022-01-25T11:29:05.447Z
I've seen them and after looking at the source of modifiesUtxoSet, I'd say that the purpose of modifiesUtxoSet is something like: "check if TxConstraints" does something"
kindofdev
CC BY-SA 4.0
2022-01-25T10:47:02.190Z
2022-01-25T10:47:02.190Z
Sjoerd Visscher
<p>I'm trying to understand how <code>Constraints.modifiesUtxoSet</code> works.
Can anyone give an example?</p>
<pre><code>modifiesUtxoSet :: forall i o. TxConstraints i o -&gt; Bool

Check whether every transaction that satisfies the constraints has to modify the UTXO set. 
</code></pre>

<plutus>
How does Constraints.modifiesUtxoSet work?
# How does Constraints.modifiesUtxoSet work?

(Asked by: username_0 on 2022-01-19)

I'm trying to understand how Constraints.modifiesUtxoSet works.
Can anyone give an example?
modifiesUtxoSet :: forall i o. TxConstraints i o -> Bool

Check whether every transaction that satisfies the constraints has to modify the UTXO set.

**Tags:** plutus

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## 1 answers

### Answer by username_1 on 2022-01-25. Score: 3

The SimpleEscrow use case uses it:
<https://playground.plutus.iohkdev.io/doc/haddock/plutus-use-cases/html/src/Plutus.Contracts.SimpleEscrow.html#refundEp>

Another example is the Crowdfunding use case:
<https://playground.plutus.iohkdev.io/doc/haddock/plutus-use-cases/html/src/Plutus.Contracts.Crowdfunding.html#contribute>

> **Comments:**
> **username_0**: I've seen them and after looking at the source of modifiesUtxoSet, I'd say that the purpose of modifiesUtxoSet is something like: "check if TxConstraints" does something"  

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