# when(platforms:configuration:traits:) Creates a build setting condition. ``` static func when(platforms: [Platform]? = nil, configuration: BuildConfiguration? = nil, traits: Set? = nil) -> BuildSettingCondition ``` ## Parameters `platforms` The applicable platforms for this build setting condition. `configuration` The applicable build configuration for this build setting condition. `traits` The applicable traits for this build setting condition. --- Copyright © 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)