How to check the Swift version at compile time

Paul Hudson    September 15th 2016    @twostraws

Swift 2.2 introduced a new #if swift build configuration option, which lets you compile certain code only if a specific version of the Swift compiler is detected. This is particularly useful for libraries that need to support multiple incompatible versions of Swift at the same time, because only one version of their code will ever be compiled.

In the example below, the print() code will be compiled, but the capital letter text will be completely ignored – but only because we're using a Swift 2.2 compiler:

#if swift(>=2.2)
print("Running Swift 2.2 or later")
#else
THIS WILL COMPILE JUST FINE IF YOU'RE
USING A SWIFT 2.2 COMPILER BECAUSE
THIS BIT IS COMPLETELY IGNORED!
#endif

Available from iOS 7.0

Did this solution work for you? Please pass it on!

Tweet

Other people are reading…

• How to print debug text in Swift
• What are the changes in Swift 1.2?
• How to unwrap an optional in Swift
• How to find the minimum of three numbers
• What’s the difference between == and ===?

About the Swift Knowledge Base

This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.