Tracking Issue for env_host_tuple

[kornelski]

Feature gate: #![feature(env_host_tuple)]

This adds the current host tuple (AKA target triple) to std::env.

The goal is to remove the need for using build scripts to save Cargo's TARGET env var (example). Tools invoking cargo often need to know the platform's default target in order to add a matching --target <tuple> arg.

It uses the term "tuple" instead of "triple", because the "host tuple" terminology has been decided in: #125579 (comment)

It uses the term "host", because:

• after std has been built, its compilation target becomes the host for programs using it.
• during cross-compilation, Cargo's build.rs scripts will get the same tuple in the HOST env var, but a different TARGET.
• the term "target" is overloaded in Rust/Cargo.

Public API

std::env::consts::HOST_TUPLE: &str

Steps / History

• Implementation: Current platform's target tuple in std::env::consts #146296
• Final comment period (FCP)¹
• Stabilization PR

Unresolved Questions

• None yet.

@rustbot label -S-tracking-unimplemented

Footnotes

1. https://std-dev-guide.rust-lang.org/feature-lifecycle/stabilization.html ↩