1 // The rustc-cfg listed below are considered public API, but it is *unstable*
2 // and outside of the normal semver guarantees:
4 // - `futures_no_atomic_cas`
5 // Assume the target does *not* support atomic CAS operations.
6 // This is usually detected automatically by the build script, but you may
7 // need to enable it manually when building for custom targets or using
8 // non-cargo build systems that don't run the build script.
10 // With the exceptions mentioned above, the rustc-cfg emitted by the build
11 // script are *not* public API.
13 #![warn(rust_2018_idioms, single_use_lifetimes)]
17 include!("no_atomic_cas.rs");
20 let target = match env::var("TARGET") {
24 "cargo:warning={}: unable to get TARGET environment variable: {}",
25 env!("CARGO_PKG_NAME"),
32 // Note that this is `no_*`, not `has_*`. This allows treating
33 // `cfg(target_has_atomic = "ptr")` as true when the build script doesn't
34 // run. This is needed for compatibility with non-cargo build systems that
35 // don't run the build script.
36 if NO_ATOMIC_CAS.contains(&&*target) {
37 println!("cargo:rustc-cfg=futures_no_atomic_cas");
40 println!("cargo:rerun-if-changed=no_atomic_cas.rs");