---
title: lookupArchives
framework: metal
role: symbol
role_heading: Instance Property
path: metal/mtl4compilertaskoptions/lookuparchives
---

# lookupArchives

An array of archive instances that can potentially accelerate a compilation task.

## Declaration

```swift
var lookupArchives: [any MTL4Archive]? { get set }
```

## Discussion

Discussion The compiler can reduce the runtime of a compilation task if it finds an entry that matches a function description within any of the archives in this array. The compiler searches the archives in the order of the array’s element. Consider adding archives to the array in scenarios that can benefit from the runtime savings, such as repeat builds or when your app can share compilation results across multiple contexts. important: Only add MTL4Archive instances to the array that are compatible with the Metal device.