1use std::env; 2use std::path::Path; 3use std::process::Command; 4 5fn main() { 6 if let Some(rustc) = rustc_version() { 7 if rustc.minor < 60 { 8 println!("cargo:warning=The cxx crate requires a rustc version 1.60.0 or newer."); 9 println!( 10 "cargo:warning=You appear to be building with: {}", 11 rustc.version, 12 ); 13 } 14 } 15} 16 17struct RustVersion { 18 version: String, 19 minor: u32, 20} 21 22fn rustc_version() -> Option<RustVersion> { 23 let rustc = env::var_os("RUSTC")?; 24 let output = Command::new(rustc).arg("--version").output().ok()?; 25 let version = String::from_utf8(output.stdout).ok()?; 26 let mut pieces = version.split('.'); 27 if pieces.next() != Some("rustc 1") { 28 return None; 29 } 30 let minor = pieces.next()?.parse().ok()?; 31 Some(RustVersion { version, minor }) 32} 33