Purpose and mechanism of a Rust build.rs script
WHAT IT TESTS: Cargo's build pipeline. OUTLINE: build.rs compiles and runs before the crate, emitting cargo: directives via stdout to set link flags, env vars, and rerun triggers; used to compile C, generate code, or probe the system.
WHAT IT TESTS: understanding of how Cargo extends compilation with host-side code generation and native linking. ANSWER OUTLINE: build.rs is a host program Cargo compiles and runs before building the crate. It communicates by printing cargo:: directives to stdout, such as rustc-link-lib, rustc-link-search, rerun-if-changed, and rustc-cfg. Typical uses are compiling bundled C with the cc crate, generating bindings, or detecting system libraries via pkg-config. RED FLAG: claiming it runs at program runtime or that it edits source files directly.
Read the original → interview
- #rust
- #cargo
- #build-scripts
- #ffi
- #linking
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