---
title: "defaultIsolation(_:_:)"
framework: swift-package-manager
role: symbol
role_heading: Type Method
path: "swift-package-manager/documentation/packagedescription/swiftsetting/defaultisolation(_:_:)"
---

# defaultIsolation(_:_:)

Set the default isolation to the given global actor type.

## Declaration

```swift
static func defaultIsolation(_ isolation: MainActor.Type?, _ condition: BuildSettingCondition? = nil) -> SwiftSetting
```

## Parameters

- `isolation`: The type of global actor to use for default actor isolation inference. The only valid arguments are MainActor.self and nil.
- `condition`: A condition that restricts the application of the build setting.

## Discussion

Discussion note: First available in PackageDescription 6.2. The compiler defaults to inferring unannotated code as nonisolated if unspecified, or if the isolation parameter is set to nil.

## See Also

### Configuring Swift Concurrency

- [strictMemorySafety(_:)](swift-package-manager/documentation/packagedescription/swiftsetting/strictmemorysafety(_:).md)