1 use std::env; 2 use std::path::Path; 3 use std::process::Command; 4 main()5fn main() { 6 cc::Build::new() 7 .file("src/cxx.cc") 8 .cpp(true) 9 .cpp_link_stdlib(None) // linked via link-cplusplus crate 10 .flag_if_supported(cxxbridge_flags::STD) 11 .warnings_into_errors(cfg!(deny_warnings)) 12 .compile("cxxbridge1"); 13 14 println!("cargo:rerun-if-changed=src/cxx.cc"); 15 println!("cargo:rerun-if-changed=include/cxx.h"); 16 println!("cargo:rustc-cfg=built_with_cargo"); 17 18 if let Some(manifest_dir) = env::var_os("CARGO_MANIFEST_DIR") { 19 let cxx_h = Path::new(&manifest_dir).join("include").join("cxx.h"); 20 println!("cargo:HEADER={}", cxx_h.to_string_lossy()); 21 } 22 23 if let Some(rustc) = rustc_version() { 24 if rustc.minor < 48 { 25 println!("cargo:warning=The cxx crate requires a rustc version 1.48.0 or newer."); 26 println!( 27 "cargo:warning=You appear to be building with: {}", 28 rustc.version, 29 ); 30 } 31 32 if rustc.minor < 52 { 33 // #![deny(unsafe_op_in_unsafe_fn)]. 34 // https://github.com/rust-lang/rust/issues/71668 35 println!("cargo:rustc-cfg=no_unsafe_op_in_unsafe_fn_lint"); 36 } 37 } 38 } 39 40 struct RustVersion { 41 version: String, 42 minor: u32, 43 } 44 rustc_version() -> Option<RustVersion>45fn rustc_version() -> Option<RustVersion> { 46 let rustc = env::var_os("RUSTC")?; 47 let output = Command::new(rustc).arg("--version").output().ok()?; 48 let version = String::from_utf8(output.stdout).ok()?; 49 let mut pieces = version.split('.'); 50 if pieces.next() != Some("rustc 1") { 51 return None; 52 } 53 let minor = pieces.next()?.parse().ok()?; 54 Some(RustVersion { version, minor }) 55 } 56