#![allow(clippy::print_literal)] use std::{env, process::exit}; fn main() { if matches!( env::var("CARGO_FEATURE_STD"), Err(env::VarError::NotPresent) ) && matches!( env::var("CARGO_FEATURE_LOG"), Err(env::VarError::NotPresent) ) { eprintln!( "Either the 'log' feature or the 'std' feature must be enabled, otherwise {}", "this crate will do nothing." ); exit(1); } }