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Parser for CARGO_ENCODED_RUSTFLAGS
==================================
[<img alt="github" src="https://img.shields.io/badge/github-dtolnay/rustflags-8da0cb?style=for-the-badge&labelColor=555555&logo=github" height="20">](https://github.com/dtolnay/rustflags)
[<img alt="crates.io" src="https://img.shields.io/crates/v/rustflags.svg?style=for-the-badge&color=fc8d62&logo=rust" height="20">](https://crates.io/crates/rustflags)
[<img alt="docs.rs" src="https://img.shields.io/badge/docs.rs-rustflags-66c2a5?style=for-the-badge&labelColor=555555&logo=docs.rs" height="20">](https://docs.rs/rustflags)
[<img alt="build status" src="https://img.shields.io/github/actions/workflow/status/dtolnay/rustflags/ci.yml?branch=master&style=for-the-badge" height="20">](https://github.com/dtolnay/rustflags/actions?query=branch%3Amaster)
`CARGO_ENCODED_RUSTFLAGS` is one of the environment variables [provided by Cargo
to build scripts][reference]. It synthesizes several sources of flags affecting
Cargo's rustc invocations that build scripts might care about:
- Flags passed via the RUSTFLAGS environment variable,
- Cargo config entries under `target.<triple>.rustflags` and
`target.<cfg>.rustflags` and `build.rustflags`, including from the
project-specific Cargo config file and the Cargo config in the user's
CARGO_HOME.
If a build script needs to make some rustc invocations, or needs to characterize
aspects of the upcoming rustc invocation, it likely needs these flags.
[reference]: https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-build-scripts
```toml
[build-dependencies]
rustflags = "0.1"
```
<br>
## Example
This build script uses the `cmake` crate to compile some C code, and must
configure it with a particular C preprocessor #define if the Rust build is being
performed with sanitizers.
```rust
// build.rs
use rustflags::Flag;
use std::env;
use std::path::PathBuf;
fn main() {
let manifest_dir = PathBuf::from(env::var_os("CARGO_MANIFEST_DIR").unwrap());
let lib_source_dir = manifest_dir.join("lib");
assert!(lib_source_dir.join("CMakeLists.txt").exists());
let mut builder = cmake::Config::new(lib_source_dir);
// Look for -Zsanitizer=address
for flag in rustflags::from_env() {
if matches!(flag, Flag::Z(z) if z == "sanitizer=address") {
builder.define("ENABLE_SANITIZERS", "ON");
builder.define("SANITIZERS", "address");
break;
}
}
builder.build();
}
```
<br>
#### License
<sup>
Licensed under either of <a href="LICENSE-APACHE">Apache License, Version
2.0</a> or <a href="LICENSE-MIT">MIT license</a> at your option.
</sup>
<br>
<sub>
Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in this crate by you, as defined in the Apache-2.0 license, shall
be dual licensed as above, without any additional terms or conditions.
</sub>
|
