<!--
{
  "availability" : [
    "iOS: 27.0.0 -",
    "iPadOS: 27.0.0 -",
    "tvOS: 27.0.0 -",
    "visionOS: 27.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "RealityKit",
  "identifier" : "/documentation/RealityKit/LowLevelMeshResource/readIndices(_:)",
  "metadataVersion" : "0.1.0",
  "role" : "Instance Method",
  "symbol" : {
    "kind" : "Instance Method",
    "modules" : [
      "RealityKit"
    ],
    "preciseIdentifier" : "s:19RealityCoreRenderer20LowLevelMeshResourceC11readIndicesyxxs7RawSpanVq_YKXEq_YKs5ErrorR_Ri_zr0_lF"
  },
  "title" : "readIndices(_:)"
}
-->

# readIndices(_:)

Reads the current contents of the index buffer synchronously on the CPU.

```
final func readIndices<R, E>(_ body: (RawSpan) throws(E) -> R) throws(E) -> R where E : Error, R : ~Copyable
```

## Parameters

`body`

A closure that receives a read-only span over the index buffer’s bytes.

## Discussion

You pass a closure that receives a read-only span representing the contents of the index buffer.
This span is valid only for the duration of the closure.

> Throws: Any error thrown by `body`.

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)