A macro to ergonomically define an item depending on a large number of #[cfg] parameters. Structured like an if-else chain, the first matching branch is the item that gets emitted.
[dependencies] cfg-if = "0.1"
#[macro_use] extern crate cfg_if; cfg_if! { if #[cfg(unix)] { fn foo() { /* unix specific functionality */ } } else if #[cfg(target_pointer_width = "32")] { fn foo() { /* non-unix, 32-bit functionality */ } } else { fn foo() { /* fallback implementation */ } } } fn main() { foo(); }
cfg-if
is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0), with portions covered by various BSD-like licenses.
See LICENSE-APACHE, and LICENSE-MIT for details.