Swift Language Working with C and Objective-C Use the C standard library
Example
Swift's C interoperability allows you to use functions and types from the C standard library.
On Linux, the C standard library is exposed via the Glibc module; on Apple platforms it's called Darwin.
#if os(macOS) || os(iOS) || os(tvOS) || os(watchOS)
import Darwin
#elseif os(Linux)
import Glibc
#endif
// use open(), read(), and other libc features
